Pub Date : 2023-10-01DOI: 10.17586/2226-1494-2023-23-5-904-910
C. Zhiqiang, L. Duzhesheng, A.Yu. Krasnov, L. Yanyu
This paper studies the trajectory tracking problem and the controller gain adjustment problem for Wheeled Mobile Robots. The controller gain has a great influence on the robot’s trajectory tracking: it can influence both the tracking accuracy and the tracking speed. Therefore, it is very important to choose a suitable control gain during the controller design process. Current neural network gain controllers have a complex structure and require a lot of calculations to find the optimal value. To solve this problem, we design a trajectory tracking controller with a simple structure with adaptive gain by combining the controller with a neural network. The input to this controller is the robot’s attitude error. The controller has no hidden layer and directly outputs the trajectory tracking control law. Firstly, the kinematic controller is designed based on Lyapunov function method to ensure that the robot moves according to the reference trajectory. Then, the online gain adjustment algorithm is designed by using neural network to realize the fast adjustment of the controller gain and ensure the reliability of the controller. Finally, the backstepping method is utilized to design the velocity tracking controller based on the error between the virtual velocity and the actual velocity. Considering the influence of the external environment, we also design a nonlinear disturbance observer to estimate the total disturbance on the robot. We perform simulation experiment in MATLAB. The result of the experiment shows that the control algorithm proposed in this paper can realize the accurate tracking of the robot on the specified trajectory. The gain adjustment algorithm we designed can find the optimal gain value quickly and efficiently, thus improving the stability and efficiency of the controller. The method can be applied to most mobile robot trajectory tracking problems and solves the problem of control gain adjustment.
{"title":"Trajectory tracking control for mobile robots with adaptive gain","authors":"C. Zhiqiang, L. Duzhesheng, A.Yu. Krasnov, L. Yanyu","doi":"10.17586/2226-1494-2023-23-5-904-910","DOIUrl":"https://doi.org/10.17586/2226-1494-2023-23-5-904-910","url":null,"abstract":"This paper studies the trajectory tracking problem and the controller gain adjustment problem for Wheeled Mobile Robots. The controller gain has a great influence on the robot’s trajectory tracking: it can influence both the tracking accuracy and the tracking speed. Therefore, it is very important to choose a suitable control gain during the controller design process. Current neural network gain controllers have a complex structure and require a lot of calculations to find the optimal value. To solve this problem, we design a trajectory tracking controller with a simple structure with adaptive gain by combining the controller with a neural network. The input to this controller is the robot’s attitude error. The controller has no hidden layer and directly outputs the trajectory tracking control law. Firstly, the kinematic controller is designed based on Lyapunov function method to ensure that the robot moves according to the reference trajectory. Then, the online gain adjustment algorithm is designed by using neural network to realize the fast adjustment of the controller gain and ensure the reliability of the controller. Finally, the backstepping method is utilized to design the velocity tracking controller based on the error between the virtual velocity and the actual velocity. Considering the influence of the external environment, we also design a nonlinear disturbance observer to estimate the total disturbance on the robot. We perform simulation experiment in MATLAB. The result of the experiment shows that the control algorithm proposed in this paper can realize the accurate tracking of the robot on the specified trajectory. The gain adjustment algorithm we designed can find the optimal gain value quickly and efficiently, thus improving the stability and efficiency of the controller. The method can be applied to most mobile robot trajectory tracking problems and solves the problem of control gain adjustment.","PeriodicalId":21700,"journal":{"name":"Scientific and Technical Journal of Information Technologies, Mechanics and Optics","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136247612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-01DOI: 10.17586/2226-1494-2023-23-5-894-903
V.H. Bui, V.A. Zhdanov, A.A. Margun
In the paper, the problem of compensation of external disturbance in multichannel systems with unmeasurable state vector and delay in the control channel is considered. It is assumed that the disturbance has a harmonic form. To solve the problem of estimating the state vector of a system, a full-order observer with Unknown Input Observer is constructed. A new observer of external disturbance is formed on the basis of the state vector estimates produced by this observer. As a result, a system is formed that uses estimates with an extended state vector. For this system, a regulator is constructed that provides compensation of the disturbance. The proposed algorithm guarantees boundedness of all signals in the closed-loop system and asymptotic stability of the output. It does not require identification of parameters of external disturbance. To demonstrate the performance and efficiency of the proposed approach, computer simulation using MATLAB Simulink software environment is performed. The developed algorithm can be effectively applied in systems with external disturbance in the form of sinusoidal signals, including systems exposed to wind, ship systems, motion control systems of robotic complexes of various types, and others.
{"title":"Robust disturbances compensation for MIMO linear systems with unmeasured state vector and control delay","authors":"V.H. Bui, V.A. Zhdanov, A.A. Margun","doi":"10.17586/2226-1494-2023-23-5-894-903","DOIUrl":"https://doi.org/10.17586/2226-1494-2023-23-5-894-903","url":null,"abstract":"In the paper, the problem of compensation of external disturbance in multichannel systems with unmeasurable state vector and delay in the control channel is considered. It is assumed that the disturbance has a harmonic form. To solve the problem of estimating the state vector of a system, a full-order observer with Unknown Input Observer is constructed. A new observer of external disturbance is formed on the basis of the state vector estimates produced by this observer. As a result, a system is formed that uses estimates with an extended state vector. For this system, a regulator is constructed that provides compensation of the disturbance. The proposed algorithm guarantees boundedness of all signals in the closed-loop system and asymptotic stability of the output. It does not require identification of parameters of external disturbance. To demonstrate the performance and efficiency of the proposed approach, computer simulation using MATLAB Simulink software environment is performed. The developed algorithm can be effectively applied in systems with external disturbance in the form of sinusoidal signals, including systems exposed to wind, ship systems, motion control systems of robotic complexes of various types, and others.","PeriodicalId":21700,"journal":{"name":"Scientific and Technical Journal of Information Technologies, Mechanics and Optics","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136247740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-01DOI: 10.17586/2226-1494-2023-23-5-1030-1040
A.V. Timofeev
A new method of guaranteed solution for multiclass classification problem of stochastic objects is proposed. Within the framework of the proposed approach, the classification result is a finite set of class indices which with a predetermined confidence coefficient contains the index of the class to which the object being classified corresponds. In this case, the classification itself is realized on the basis of using a classifier of the new type which is called a confidence Lipschitz classifier. The definition of the confidence Lipschitz classifier is given and its main properties have been studied. Among them, the property of guaranteed reliability of the classification which is expressed in the construction of a confidence set of limited size containing the index of the true class with a predetermined coefficient of confidence, has been studied. The case of the assembly of Lipschitz classifiers, the properties of which are formalized in the form of a theorem, is considered. We consider a practically important example of using the proposed approach in the problems of compensation of the noise process dynamics in the channels of the fiber-optic monitoring system. The proposed approach is promising for use in those classification tasks in which the number of classes has an order higher than the second, including large-scale biometric identification systems as well as multi-channel systems for monitoring extended objects.
{"title":"Confidence Lipschitz classifiers: an instrument of guaranteed reliability","authors":"A.V. Timofeev","doi":"10.17586/2226-1494-2023-23-5-1030-1040","DOIUrl":"https://doi.org/10.17586/2226-1494-2023-23-5-1030-1040","url":null,"abstract":"A new method of guaranteed solution for multiclass classification problem of stochastic objects is proposed. Within the framework of the proposed approach, the classification result is a finite set of class indices which with a predetermined confidence coefficient contains the index of the class to which the object being classified corresponds. In this case, the classification itself is realized on the basis of using a classifier of the new type which is called a confidence Lipschitz classifier. The definition of the confidence Lipschitz classifier is given and its main properties have been studied. Among them, the property of guaranteed reliability of the classification which is expressed in the construction of a confidence set of limited size containing the index of the true class with a predetermined coefficient of confidence, has been studied. The case of the assembly of Lipschitz classifiers, the properties of which are formalized in the form of a theorem, is considered. We consider a practically important example of using the proposed approach in the problems of compensation of the noise process dynamics in the channels of the fiber-optic monitoring system. The proposed approach is promising for use in those classification tasks in which the number of classes has an order higher than the second, including large-scale biometric identification systems as well as multi-channel systems for monitoring extended objects.","PeriodicalId":21700,"journal":{"name":"Scientific and Technical Journal of Information Technologies, Mechanics and Optics","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136247734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We carried out the development and study of methods for changing the sensitivity of Fiber Bragg Gratings (FBG) to temperature and strain by applying various low-melting metals. Investigation of sensitive elements based on SMF-28 single-mode optical fibers with formed FBG and various metal coatings applied over the fiber have been made. The influence of FBG coating with low-melting metals on its sensitivity to temperature and deformation has been studied. Various fiber-optic sensitive elements have been developed, which are fibers with fiber Bragg gratings formed in them, while coatings of various thicknesses of tin or solder in the form of an alloy of tin and lead (Sn63Pb37) were deposited on the area with such diffraction structures. The presented experimental data are in good agreement with the calculated ones. The temperature sensitivity of the Bragg grating resonance with a solder or tin coatings is 4 times higher than the sensitivity of an uncoated grating. In turn, the analysis of the sensitivity to stretching allows us to conclude that, in comparison with the standard FBG, the sensitivity of the grating in the coating decreases and is about 0.017 pm/(µm/m) compared to 1.2 pm/(µm/m) (for the wavelength of the Bragg resonance 1530 nm) for a standard FBG without coating. The results obtained can be used to control and change the FBG sensitivity to temperature and/or deformation, depending on the conditions of the problem being solved in the field of creating fiber-optic measuring devices.
{"title":"Investigation of changes in the sensitivity of a fiber Bragg grating to temperature and strain using coatings from low-melting metal","authors":"E.A. Maiorova, S.V. Varzhel, V.A. Klishina, A.I. Kozlova","doi":"10.17586/2226-1494-2023-23-5-871-877","DOIUrl":"https://doi.org/10.17586/2226-1494-2023-23-5-871-877","url":null,"abstract":"We carried out the development and study of methods for changing the sensitivity of Fiber Bragg Gratings (FBG) to temperature and strain by applying various low-melting metals. Investigation of sensitive elements based on SMF-28 single-mode optical fibers with formed FBG and various metal coatings applied over the fiber have been made. The influence of FBG coating with low-melting metals on its sensitivity to temperature and deformation has been studied. Various fiber-optic sensitive elements have been developed, which are fibers with fiber Bragg gratings formed in them, while coatings of various thicknesses of tin or solder in the form of an alloy of tin and lead (Sn63Pb37) were deposited on the area with such diffraction structures. The presented experimental data are in good agreement with the calculated ones. The temperature sensitivity of the Bragg grating resonance with a solder or tin coatings is 4 times higher than the sensitivity of an uncoated grating. In turn, the analysis of the sensitivity to stretching allows us to conclude that, in comparison with the standard FBG, the sensitivity of the grating in the coating decreases and is about 0.017 pm/(µm/m) compared to 1.2 pm/(µm/m) (for the wavelength of the Bragg resonance 1530 nm) for a standard FBG without coating. The results obtained can be used to control and change the FBG sensitivity to temperature and/or deformation, depending on the conditions of the problem being solved in the field of creating fiber-optic measuring devices.","PeriodicalId":21700,"journal":{"name":"Scientific and Technical Journal of Information Technologies, Mechanics and Optics","volume":"167 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136248027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-01DOI: 10.17586/2226-1494-2023-23-5-1009-1020
G.M. Soma, G.D. Kopanitsa
In this paper, we have developed a system for assigning customers to the routes based on their emotional state and age in Public Service Systems (PSSs). The Squeeze-and-Excitation (SE) method was used to develop the models, it improves the efficiency of the Deep Convolutional Neural Networks (DCNN) architecture by increasing the information flow between layers and enhancing important features. The method is based on compressing and exciting information at each convolution stage, which allows obtaining a vector of channel importance scores and using it to reweight the channels of the feature map. The study showed that this method allowed improving the quality of classification and reducing the model training time. The model of emotional target routing was developed based on the Newton interpolation polynomial to route customers based on their emotional state and age. The interpolation function in this model calculates the waiting time for customers according to their emotional state. Three models of binary classification of emotions and ages were developed, namely, two models for recognizing the emotional state of the customer, and one model for recognizing their age. The first and third models utilize DCNN from scratch using the new SE approach based on the attention mechanism. The second model uses the Support Vector Machine (SVM) method. The evaluate method was used to test the model after training, which allows evaluating the quality of the model on new data that was not used during training. This is done to check how accurately the model can predict the values of the target variable on new data. The evaluate method utilizes quality evaluation metrics such as accuracy, recall, and F1-score to assess the performance of the model. According to the experimental data obtained, the first and the second developed models achieved the validation accuracy of 72 % and 66 %, respectively, on the FER-2013 and Adience datasets. Their sizes were 0.69 MB and 369 MB, respectively. At the same time, the age recognition model achieved the accuracy of 88 % with the size of 1.68 MB. The mathematical model of emotional target routing (TERSS) was developed to minimize conflicts in public service systems. The developed system can automatically route customers based on their emotional state (presence of anger) and age to the appropriate operator. Thus, customers over 60 years old or with the anger level of 60–80 % are directed to a senior operator who knows how to communicate with elderly or emotionally excited customers, while customers with the anger level of 80–100 % are directed to a psychologist. This research can be applied in PSSs to detect the features of customers’ age and anger. Moreover, it can be applied in various areas where there is a contact with a large number of people, such as banks, supermarkets, airports access control systems, police stations, subways, and call centers.
{"title":"System for customers' routing based on their emotional state and age in public services systems","authors":"G.M. Soma, G.D. Kopanitsa","doi":"10.17586/2226-1494-2023-23-5-1009-1020","DOIUrl":"https://doi.org/10.17586/2226-1494-2023-23-5-1009-1020","url":null,"abstract":"In this paper, we have developed a system for assigning customers to the routes based on their emotional state and age in Public Service Systems (PSSs). The Squeeze-and-Excitation (SE) method was used to develop the models, it improves the efficiency of the Deep Convolutional Neural Networks (DCNN) architecture by increasing the information flow between layers and enhancing important features. The method is based on compressing and exciting information at each convolution stage, which allows obtaining a vector of channel importance scores and using it to reweight the channels of the feature map. The study showed that this method allowed improving the quality of classification and reducing the model training time. The model of emotional target routing was developed based on the Newton interpolation polynomial to route customers based on their emotional state and age. The interpolation function in this model calculates the waiting time for customers according to their emotional state. Three models of binary classification of emotions and ages were developed, namely, two models for recognizing the emotional state of the customer, and one model for recognizing their age. The first and third models utilize DCNN from scratch using the new SE approach based on the attention mechanism. The second model uses the Support Vector Machine (SVM) method. The evaluate method was used to test the model after training, which allows evaluating the quality of the model on new data that was not used during training. This is done to check how accurately the model can predict the values of the target variable on new data. The evaluate method utilizes quality evaluation metrics such as accuracy, recall, and F1-score to assess the performance of the model. According to the experimental data obtained, the first and the second developed models achieved the validation accuracy of 72 % and 66 %, respectively, on the FER-2013 and Adience datasets. Their sizes were 0.69 MB and 369 MB, respectively. At the same time, the age recognition model achieved the accuracy of 88 % with the size of 1.68 MB. The mathematical model of emotional target routing (TERSS) was developed to minimize conflicts in public service systems. The developed system can automatically route customers based on their emotional state (presence of anger) and age to the appropriate operator. Thus, customers over 60 years old or with the anger level of 60–80 % are directed to a senior operator who knows how to communicate with elderly or emotionally excited customers, while customers with the anger level of 80–100 % are directed to a psychologist. This research can be applied in PSSs to detect the features of customers’ age and anger. Moreover, it can be applied in various areas where there is a contact with a large number of people, such as banks, supermarkets, airports access control systems, police stations, subways, and call centers.","PeriodicalId":21700,"journal":{"name":"Scientific and Technical Journal of Information Technologies, Mechanics and Optics","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136247735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-01DOI: 10.17586/2226-1494-2023-23-5-878-885
E.E. Kalugin, V.E. Strigalev, A.B. Mukhtubaev, I.K. Meshkovskii
One of the applications of polarization maintaining (PM) fibers is the creation of various sensors including level and hydrostatic pressure sensors. An external mechanical stress on a PM fiber causes cross-polarization coupling. In micro- and macro-bend pressure sensors, the attenuation of the optical signal increases with increasing external pressure. Combination of two physical principles in one sensor allows to create fiber-optic sensors of high sensitivity for operation at pressure more than 18 kPa. At the same time, the registration scheme is significantly simplified. An optical fiber with an elliptical ESC-4 stress cladding was used as a prototype. A superluminiscent diode ThorLabs S5FC1005SXL with a center wavelength of 1560 nm and a spectrum half-width of 45 nm was used in the study. In this work, the effect of induced periodic mechanical stress on cross-polarization coupling magnitude in a PM fiber with an elliptical stress cladding was considered. The induced periodic stress was generated by a proposed and specially fabricated periodic structure of optical fiber sections bonded to a glass substrate. The pressure on the fiber prototype was changed by weights of known mass as well as by rotating the fiber around its axis with a step of 5°. Hydrostatic pressure was created by means of a water tank placed in the barocamera. The cross-polarization coupled power was recorded with two photodetectors using a polarization beam splitter. It is shown that the largest value of the relative coupled power is achieved at the period of mechanical stress equal to the beat length of PM fiber. The dependence of the relative coupled power on the hydrostatic pressure is obtained for the prototype sensor. It is shown that the highest value of the relative coupled power is achieved at a pressure of 80 kPa. The threshold sensitivity amounted to 20 kPa. The decrease in coupled power at pressures greater than 80 kPa is attributed to induced optical losses. At pressure less than 20 kPa, a hysteresis of indicators up to 0.006 relative units is noticeable. A sample sensor for measuring hydrostatic pressure up to 80 kPa with the standard deviation of measurement results up to 7 % was obtained. The threshold sensitivity is limited to 20 kPa. The performed research can be applied in the development of fiber-optic pressure sensors.
{"title":"Cross-polarization coupling in polarization maintaining fiber induced by periodic mechanical stress","authors":"E.E. Kalugin, V.E. Strigalev, A.B. Mukhtubaev, I.K. Meshkovskii","doi":"10.17586/2226-1494-2023-23-5-878-885","DOIUrl":"https://doi.org/10.17586/2226-1494-2023-23-5-878-885","url":null,"abstract":"One of the applications of polarization maintaining (PM) fibers is the creation of various sensors including level and hydrostatic pressure sensors. An external mechanical stress on a PM fiber causes cross-polarization coupling. In micro- and macro-bend pressure sensors, the attenuation of the optical signal increases with increasing external pressure. Combination of two physical principles in one sensor allows to create fiber-optic sensors of high sensitivity for operation at pressure more than 18 kPa. At the same time, the registration scheme is significantly simplified. An optical fiber with an elliptical ESC-4 stress cladding was used as a prototype. A superluminiscent diode ThorLabs S5FC1005SXL with a center wavelength of 1560 nm and a spectrum half-width of 45 nm was used in the study. In this work, the effect of induced periodic mechanical stress on cross-polarization coupling magnitude in a PM fiber with an elliptical stress cladding was considered. The induced periodic stress was generated by a proposed and specially fabricated periodic structure of optical fiber sections bonded to a glass substrate. The pressure on the fiber prototype was changed by weights of known mass as well as by rotating the fiber around its axis with a step of 5°. Hydrostatic pressure was created by means of a water tank placed in the barocamera. The cross-polarization coupled power was recorded with two photodetectors using a polarization beam splitter. It is shown that the largest value of the relative coupled power is achieved at the period of mechanical stress equal to the beat length of PM fiber. The dependence of the relative coupled power on the hydrostatic pressure is obtained for the prototype sensor. It is shown that the highest value of the relative coupled power is achieved at a pressure of 80 kPa. The threshold sensitivity amounted to 20 kPa. The decrease in coupled power at pressures greater than 80 kPa is attributed to induced optical losses. At pressure less than 20 kPa, a hysteresis of indicators up to 0.006 relative units is noticeable. A sample sensor for measuring hydrostatic pressure up to 80 kPa with the standard deviation of measurement results up to 7 % was obtained. The threshold sensitivity is limited to 20 kPa. The performed research can be applied in the development of fiber-optic pressure sensors.","PeriodicalId":21700,"journal":{"name":"Scientific and Technical Journal of Information Technologies, Mechanics and Optics","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136247544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The work is devoted to the study of the characteristics of the state control of a thin-film element based on a phase-change GeTe material. The properties of such an element have been controlled by the action of sequences of ultrashort laser pulses. This action leads to a rapid heating of the thin film element and provides a phase transition between states with a resistance different by several orders of magnitude. The dynamics of the resistance was studied using a high speed oscilloscope according to the scheme where the element under study was the voltage divider arm of a highly stable source. Three different types of conductivity switching were observed for 100 nm thin films. For low energy laser radiation, several distinct states were obtained in which the material film has predominantly semiconducting properties. As the energy of the optical pulses increases, the number of possible stable states determined by the specific conductivity of the material decreases to two, one of which (low resistance) is exclusively metallic properties. In all cases, the time taken to switch to a stable state does not exceed a few tens of nanoseconds for films up to 100 nm thick. The study has demonstrated that the structures described can be used to implement optically controlled memristive elements. In addition, the large number of possible allowable specific resistances of the element will make it possible to use it to increase the information capacity of memory cells based on phase-change materials or to implement optoelectronic neuromorphic systems.
{"title":"Switching the electrical properties of thin-film memristive elements based on GeTe by sequences of ultrashort laser pulses","authors":"N.N. Eliseev, A.A. Nevzorov, V.A. Mikhalevsky, A.V. Kiselev, A.A. Burtsev, V.V. Ionin, A.A. Lotin","doi":"10.17586/2226-1494-2023-23-5-911-919","DOIUrl":"https://doi.org/10.17586/2226-1494-2023-23-5-911-919","url":null,"abstract":"The work is devoted to the study of the characteristics of the state control of a thin-film element based on a phase-change GeTe material. The properties of such an element have been controlled by the action of sequences of ultrashort laser pulses. This action leads to a rapid heating of the thin film element and provides a phase transition between states with a resistance different by several orders of magnitude. The dynamics of the resistance was studied using a high speed oscilloscope according to the scheme where the element under study was the voltage divider arm of a highly stable source. Three different types of conductivity switching were observed for 100 nm thin films. For low energy laser radiation, several distinct states were obtained in which the material film has predominantly semiconducting properties. As the energy of the optical pulses increases, the number of possible stable states determined by the specific conductivity of the material decreases to two, one of which (low resistance) is exclusively metallic properties. In all cases, the time taken to switch to a stable state does not exceed a few tens of nanoseconds for films up to 100 nm thick. The study has demonstrated that the structures described can be used to implement optically controlled memristive elements. In addition, the large number of possible allowable specific resistances of the element will make it possible to use it to increase the information capacity of memory cells based on phase-change materials or to implement optoelectronic neuromorphic systems.","PeriodicalId":21700,"journal":{"name":"Scientific and Technical Journal of Information Technologies, Mechanics and Optics","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136247610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-01DOI: 10.17586/2226-1494-2023-23-5-989-1000
D.A. Kleverov, A.A. Shalyto, M.N. Artyomov
Solving the problem of predicting the immune response against foreign protein sequence fragments processed by cells is one of the major milestones on the road to the personalized cancer vaccine development. The selection of peptides participating in the immune response is a complex multi-stage process of filtering initial sequences to present their fragments on the cell surface. The most studied task regarding this filtering nowadays is the prediction of the binding probability of peptides to major histocompatibility complex molecules. Modern methods for predicting this stage are usually based on algorithms using artificial neural networks, which make it impossible to interpret the result predictions of such models. One of the methods to overcome this limitation is the use of interpretable hidden Markov models. In this work, an analysis of the binding prediction task is performed. As a result, a method for constructing interpretable models that consider domain-specific constraints and requirements is proposed. A method for the constriction, training and interpretation of hidden Markov models was proposed for each class of molecules. The construction and training are based on maintaining the model architecture capable of extracting and visualizing the binding core of the peptide. Interpretation is possible through the analysis of the model graph. The proposed method is tested in the task of training a model that not only enables prediction but also facilitates determining the position of the peptide binding core and the distribution of amino acids within the core. Prediction models were trained for two types of molecules using binding data. The distributions of amino acids in the binding core match the state distributions of the model. Sequence patterns of such regions extracted using the trained models for two sets of peptide data correspond to patterns from public databases, confirming the successful validation of the method. Interpretable models provide a better description of the problem domain and help to draw a conclusion about peptide characteristics based on information extracted from the model. This information will allow researchers to better understand other steps of peptide processing involved in the immune response. For example, one can study relationships between these steps or perform a transfer of knowledge from models trained for one step to others. Using this knowledge will allow the training of the models under conditions of limited training data.
{"title":"A method for constructing interpretable hidden Markov models for the task of identifying binding cores in sequences","authors":"D.A. Kleverov, A.A. Shalyto, M.N. Artyomov","doi":"10.17586/2226-1494-2023-23-5-989-1000","DOIUrl":"https://doi.org/10.17586/2226-1494-2023-23-5-989-1000","url":null,"abstract":"Solving the problem of predicting the immune response against foreign protein sequence fragments processed by cells is one of the major milestones on the road to the personalized cancer vaccine development. The selection of peptides participating in the immune response is a complex multi-stage process of filtering initial sequences to present their fragments on the cell surface. The most studied task regarding this filtering nowadays is the prediction of the binding probability of peptides to major histocompatibility complex molecules. Modern methods for predicting this stage are usually based on algorithms using artificial neural networks, which make it impossible to interpret the result predictions of such models. One of the methods to overcome this limitation is the use of interpretable hidden Markov models. In this work, an analysis of the binding prediction task is performed. As a result, a method for constructing interpretable models that consider domain-specific constraints and requirements is proposed. A method for the constriction, training and interpretation of hidden Markov models was proposed for each class of molecules. The construction and training are based on maintaining the model architecture capable of extracting and visualizing the binding core of the peptide. Interpretation is possible through the analysis of the model graph. The proposed method is tested in the task of training a model that not only enables prediction but also facilitates determining the position of the peptide binding core and the distribution of amino acids within the core. Prediction models were trained for two types of molecules using binding data. The distributions of amino acids in the binding core match the state distributions of the model. Sequence patterns of such regions extracted using the trained models for two sets of peptide data correspond to patterns from public databases, confirming the successful validation of the method. Interpretable models provide a better description of the problem domain and help to draw a conclusion about peptide characteristics based on information extracted from the model. This information will allow researchers to better understand other steps of peptide processing involved in the immune response. For example, one can study relationships between these steps or perform a transfer of knowledge from models trained for one step to others. Using this knowledge will allow the training of the models under conditions of limited training data.","PeriodicalId":21700,"journal":{"name":"Scientific and Technical Journal of Information Technologies, Mechanics and Optics","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136247613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-01DOI: 10.17586/2226-1494-2023-23-5-1050-1055
A.V. Sharamet, A.N. Lysy
The solution of the mathematical problem of rotation of a three-dimensional surface in space with an orthogonal basis and its mapping on a plane using simple geometric shapes is considered. This task arises when accompanying moving objects against the background of the surrounding environment. A design feature of such systems is that they contain functional additional elements that provide information about the maneuvering object of observation and generate control signals to work out the error that has occurred. This operation is performed continuously in real time. It is assumed that this problem is solved using a digital computer, i.e., the change in the angle of sight of the observed moving object will be recorded in separate time intervals — partial (discrete) ones. The initial state of the coordinate system can be represented in matrix form, respectively; the transition to the final state is carried out at discrete points in time. The problem is solved analytically. A number of restrictions on the magnitude of vectors and their mutual orientation in space are formulated. The proposed approach made it possible to increase the visibility and predictability of the operations performed due to the transition from nonlinear trigonometric equations to the simplest linear operations. To demonstrate the correctness of the implementation and clarity of the application of the proposed vector-algebraic approach, the background of the environment is presented in *.off format (geomview object file format). Finite expressions are obtained for the rotation of the coordinate system of an elastic body with a fixed center of mass. The solutions obtained are formalized on the basis of strict mathematical transformations and belong to the class of problems in which analytical relations accurately describe the data, that is, when, in the absence of measurement errors, the residual vector of the system is always zero. This approach allows you to avoid performing transformations on complex nonlinear mathematical expressions.
{"title":"Solving the problem of spatial rotation of 3D surfaces and their mapping on the plane","authors":"A.V. Sharamet, A.N. Lysy","doi":"10.17586/2226-1494-2023-23-5-1050-1055","DOIUrl":"https://doi.org/10.17586/2226-1494-2023-23-5-1050-1055","url":null,"abstract":"The solution of the mathematical problem of rotation of a three-dimensional surface in space with an orthogonal basis and its mapping on a plane using simple geometric shapes is considered. This task arises when accompanying moving objects against the background of the surrounding environment. A design feature of such systems is that they contain functional additional elements that provide information about the maneuvering object of observation and generate control signals to work out the error that has occurred. This operation is performed continuously in real time. It is assumed that this problem is solved using a digital computer, i.e., the change in the angle of sight of the observed moving object will be recorded in separate time intervals — partial (discrete) ones. The initial state of the coordinate system can be represented in matrix form, respectively; the transition to the final state is carried out at discrete points in time. The problem is solved analytically. A number of restrictions on the magnitude of vectors and their mutual orientation in space are formulated. The proposed approach made it possible to increase the visibility and predictability of the operations performed due to the transition from nonlinear trigonometric equations to the simplest linear operations. To demonstrate the correctness of the implementation and clarity of the application of the proposed vector-algebraic approach, the background of the environment is presented in *.off format (geomview object file format). Finite expressions are obtained for the rotation of the coordinate system of an elastic body with a fixed center of mass. The solutions obtained are formalized on the basis of strict mathematical transformations and belong to the class of problems in which analytical relations accurately describe the data, that is, when, in the absence of measurement errors, the residual vector of the system is always zero. This approach allows you to avoid performing transformations on complex nonlinear mathematical expressions.","PeriodicalId":21700,"journal":{"name":"Scientific and Technical Journal of Information Technologies, Mechanics and Optics","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136247736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-01DOI: 10.17586/2226-1494-2023-23-5-1001-1008
N.V. Kolesov, E.G. Litunenko, Iu.M. Skorodumov, M.V. Tolmacheva
Scheduling of computing operations takes an important place in the process of distributed information processing and control systems design, especially in conditions of limited energy resources of the system. This becomes especially important for computers located on autonomous carriers, such as unmanned aerial vehicles, autonomous underwater vehicles, etc. The energy resources in such systems are limited that leads to high requirements for the energy efficiency of the carrier systems including computing ones. The paper presents the job scheduling method for a distributed computing system on a chip which allows reducing the power consumed by the system. The proposed task scheduling method includes two stages. At the first stage, jobs are assigned with the determination of an energy-efficient architecture of the system characterized by the minimum power consumption. At the second stage, jobs are scheduled taking into account the criterion that minimalizes the average job implementation time. A feature of the problem being solved in this case is the necessity of job scheduling in the system with more than one information output which does not allow applying any of the known scheduling methods to the system. The first stage of the proposed method is implemented by implementation additional processors with a simultaneous decrease in the clock frequency and supply voltage. For the second stage of the method, the job scheduling algorithm is proposed which involves the preliminary construction of a private schedule for each output of the system with further integration of these schedules into the general schedule using a heuristic procedure. The scheduling algorithm functioning is illustrated by an example of a solution for a simple system. The advantage of the proposed heuristic method is the possibility of scheduling calculations, taking into account criteria of the minimum power consumption and the minimum average residence time of a task in the system simultaniously. This makes it possible to increase the energy efficiency of solving problems in distributed computing systems on a chip, which contributes to increasing the autonomy of systems in which they are used in. The proposed algorithm has polynomial complexity, therefore, due to the relative simplicity of the algorithm, it can be used for scheduling and rescheduling jobs in real time for complex systems.
{"title":"Job scheduling in a distributed computing system on a chip with power consumption minimization","authors":"N.V. Kolesov, E.G. Litunenko, Iu.M. Skorodumov, M.V. Tolmacheva","doi":"10.17586/2226-1494-2023-23-5-1001-1008","DOIUrl":"https://doi.org/10.17586/2226-1494-2023-23-5-1001-1008","url":null,"abstract":"Scheduling of computing operations takes an important place in the process of distributed information processing and control systems design, especially in conditions of limited energy resources of the system. This becomes especially important for computers located on autonomous carriers, such as unmanned aerial vehicles, autonomous underwater vehicles, etc. The energy resources in such systems are limited that leads to high requirements for the energy efficiency of the carrier systems including computing ones. The paper presents the job scheduling method for a distributed computing system on a chip which allows reducing the power consumed by the system. The proposed task scheduling method includes two stages. At the first stage, jobs are assigned with the determination of an energy-efficient architecture of the system characterized by the minimum power consumption. At the second stage, jobs are scheduled taking into account the criterion that minimalizes the average job implementation time. A feature of the problem being solved in this case is the necessity of job scheduling in the system with more than one information output which does not allow applying any of the known scheduling methods to the system. The first stage of the proposed method is implemented by implementation additional processors with a simultaneous decrease in the clock frequency and supply voltage. For the second stage of the method, the job scheduling algorithm is proposed which involves the preliminary construction of a private schedule for each output of the system with further integration of these schedules into the general schedule using a heuristic procedure. The scheduling algorithm functioning is illustrated by an example of a solution for a simple system. The advantage of the proposed heuristic method is the possibility of scheduling calculations, taking into account criteria of the minimum power consumption and the minimum average residence time of a task in the system simultaniously. This makes it possible to increase the energy efficiency of solving problems in distributed computing systems on a chip, which contributes to increasing the autonomy of systems in which they are used in. The proposed algorithm has polynomial complexity, therefore, due to the relative simplicity of the algorithm, it can be used for scheduling and rescheduling jobs in real time for complex systems.","PeriodicalId":21700,"journal":{"name":"Scientific and Technical Journal of Information Technologies, Mechanics and Optics","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136247737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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