Pub Date : 2021-10-21DOI: 10.7225/toms.v10.n02.w05
Nur Syafiqa Aifa Shahrom, Naiem Mohd Azzeri, Mohd Shukri Mohd Yusop, Mohd Norsyarizad Razali, Mohd Najib Abdul Ghani Yolhamid, A. Rahman, Sarah Isnan, Afiqah Rosly, Mohd Arif Ahmad
This paper presents a research to determine the effects of the Northeast Monsoon (NEM) and the Southwest Monsoon (SWM) on wave power along the coastal area of Mandi Darah Island, Sabah. This study identified the daily data of wave height and wave period for 6 months from June to December 2018. The following period was chosen because it consisted of two monsoon seasons in Sabah. The data obtained from the Acoustic Doppler Current Profiler (ADCP) were thoroughly analyzed to estimate the wave height and the wave period to identify the wave power at Mandi Darah Island. The wave heights ranged from 0.01 m to 0.47 m while the wave periods ranged from 1.0 s to 8.6 s. The wave height range during the NEM was higher by 0.12 m than SWM, while the difference of wave period was significantly higher by 2.17 s during the NEM. The maximum wave power recorded at Mandi Darah Island was 1.57 kW/m throughout the period. During NEM, the wave power was significantly higher than during SWM, by 0.70 kW/m. These findings led to determining the wave energy type converter that suits the wave conditions at the Mandi Darah Island coastal area.
本文研究了东北季风(NEM)和西南季风(SWM)对沙巴州Mandi Darah岛沿海地区波浪能的影响。本研究确定了2018年6月至12月6个月的每日波高和波周期数据。之所以选择下面这段时间，是因为它包含了沙巴的两个季风季节。利用声波多普勒电流剖面仪(ADCP)的数据进行分析，估算了Mandi Darah岛的波高和波周期，从而确定了岛上的波浪能。波高为0.01 m ~ 0.47 m，波周期为1.0 s ~ 8.6 s。新气象期间的波高差比新气象期间的波高差大0.12 m，波周期差比新气象期间的波高差大2.17 s。在此期间，曼迪达拉岛录得的最大海浪功率为1.57千瓦/米。在NEM期间，波浪功率明显高于SWM期间，提高了0.70 kW/m。这些发现有助于确定适合Mandi Darah岛沿海地区波浪条件的波能型转换器。
{"title":"Feasibility Study of Monsoon Effect on Wave Power for Wave Energy Converter in Sabah, Malaysia","authors":"Nur Syafiqa Aifa Shahrom, Naiem Mohd Azzeri, Mohd Shukri Mohd Yusop, Mohd Norsyarizad Razali, Mohd Najib Abdul Ghani Yolhamid, A. Rahman, Sarah Isnan, Afiqah Rosly, Mohd Arif Ahmad","doi":"10.7225/toms.v10.n02.w05","DOIUrl":"https://doi.org/10.7225/toms.v10.n02.w05","url":null,"abstract":"This paper presents a research to determine the effects of the Northeast Monsoon (NEM) and the Southwest Monsoon (SWM) on wave power along the coastal area of Mandi Darah Island, Sabah. This study identified the daily data of wave height and wave period for 6 months from June to December 2018. The following period was chosen because it consisted of two monsoon seasons in Sabah. The data obtained from the Acoustic Doppler Current Profiler (ADCP) were thoroughly analyzed to estimate the wave height and the wave period to identify the wave power at Mandi Darah Island. The wave heights ranged from 0.01 m to 0.47 m while the wave periods ranged from 1.0 s to 8.6 s. The wave height range during the NEM was higher by 0.12 m than SWM, while the difference of wave period was significantly higher by 2.17 s during the NEM. The maximum wave power recorded at Mandi Darah Island was 1.57 kW/m throughout the period. During NEM, the wave power was significantly higher than during SWM, by 0.70 kW/m. These findings led to determining the wave energy type converter that suits the wave conditions at the Mandi Darah Island coastal area.","PeriodicalId":42576,"journal":{"name":"Transactions on Maritime Science-ToMS","volume":"28 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80788793","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 : 2021-10-21DOI: 10.7225/toms.v10.n02.013
M. A. Abu Zarim, M. Omar
Aircraft and helicopter often fly above open waters and thus have to observe regulations to ensure safe water landing under emergency conditions. This practice is also referred to as ditching - one of several types of slamming problems that are under review by the current regulations of the Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA). Ditching is related to the controlled landing on water, with distinctive features such as hydrodynamic slamming loads, complex hydromechanics at tremendous forward speeds, as well as the interaction of multiphase fluid dynamics (air, water, and vapor). This paper presents the knowledge on system mechanics during helicopter ditching. The discussion begins with the fundamental kinetics of the rigid body, and then delves into dynamic relations to describe the effect of forces on motions. In the end, the paper discusses several relevant theories to further contribute to the understanding of the problem of impact.
{"title":"Dynamic Mechanics of Rigid Helicopter Systems During Ditching","authors":"M. A. Abu Zarim, M. Omar","doi":"10.7225/toms.v10.n02.013","DOIUrl":"https://doi.org/10.7225/toms.v10.n02.013","url":null,"abstract":"Aircraft and helicopter often fly above open waters and thus have to observe regulations to ensure safe water landing under emergency conditions. This practice is also referred to as ditching - one of several types of slamming problems that are under review by the current regulations of the Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA). Ditching is related to the controlled landing on water, with distinctive features such as hydrodynamic slamming loads, complex hydromechanics at tremendous forward speeds, as well as the interaction of multiphase fluid dynamics (air, water, and vapor). This paper presents the knowledge on system mechanics during helicopter ditching. The discussion begins with the fundamental kinetics of the rigid body, and then delves into dynamic relations to describe the effect of forces on motions. In the end, the paper discusses several relevant theories to further contribute to the understanding of the problem of impact.","PeriodicalId":42576,"journal":{"name":"Transactions on Maritime Science-ToMS","volume":"13 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82987054","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 : 2021-10-21DOI: 10.7225/toms.v10.n02.011
A. Ismail, Fatin Nur Zulkipli, M. Awang, F. A. Rahman, P. Khalid, B. A. Baharudin
Welding parameters for pipe joint friction stir welding (FSW) have been identified based on L-9 orthogonal arrays used in the Taguchi Method. Different welding parameters, such as rotation speed, travel speed and axial force, have been used to produce several quality friction stir welded AA6063 pipe butt joints. The reliability of products obtained in the FSW process can be improved through the identification of the optimum combination of welding parameters. Weld quality was evaluated based on its tensile strength and residual stress profiles. The S/N analysis and Analysis of Variance (ANOVA) have been used to determine significant welding parameters that affect weld quality. Maximum tensile strength with acceptable residual stress was obtained at the optimum welding parameters of 1300 rpm, 5 mm/s and axial force between 5 and 6 kN. The goal of this study was to optimize welding parameters for high tensile strength and low residual stress.
{"title":"Optimum Welding Parameters for Friction Stir Welded AA6063 Pipe Butt Joint Using the Taguchi Method","authors":"A. Ismail, Fatin Nur Zulkipli, M. Awang, F. A. Rahman, P. Khalid, B. A. Baharudin","doi":"10.7225/toms.v10.n02.011","DOIUrl":"https://doi.org/10.7225/toms.v10.n02.011","url":null,"abstract":"Welding parameters for pipe joint friction stir welding (FSW) have been identified based on L-9 orthogonal arrays used in the Taguchi Method. Different welding parameters, such as rotation speed, travel speed and axial force, have been used to produce several quality friction stir welded AA6063 pipe butt joints. The reliability of products obtained in the FSW process can be improved through the identification of the optimum combination of welding parameters. Weld quality was evaluated based on its tensile strength and residual stress profiles. The S/N analysis and Analysis of Variance (ANOVA) have been used to determine significant welding parameters that affect weld quality. Maximum tensile strength with acceptable residual stress was obtained at the optimum welding parameters of 1300 rpm, 5 mm/s and axial force between 5 and 6 kN. The goal of this study was to optimize welding parameters for high tensile strength and low residual stress.","PeriodicalId":42576,"journal":{"name":"Transactions on Maritime Science-ToMS","volume":"60 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79543741","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 : 2021-10-21DOI: 10.7225/toms.v10.n02.w06
N. Sridewi, Siti Nurbariah, Syahida Ahmad
Aim: Used oil-based drilling muds (OBDMs) are toxic to marine organisms due to the fluid’s complex chemical nature. The illegal dumping of used OBDMs is still rampant in many parts of the world despite of the stringent laws and regulations pertaining to its disposal. To date, study of the assessment of heavy metal content in used OBDMs from the Malaysian oil and gas industry has been limited. Furthermore, the study of the toxic effect of OBDMs using a zebrafish embryo model has never been reported before. Therefore, in this research, the used oil-based drilling muds (OBDMs) were analyzed for their heavy metal content and toxicity against Zebrafish embryos. Methods: Used OBDMs were collected from an Anchor Handling Tug Supply (AHTS) vessel mud tank from Kemaman, Terengganu. The heavy metal content in the mud was analyzed using ICP-AES. Zebrafish embryos were exposed to OBDMs of varying concentrations (i.e., 0.25 mg/ml, 0.125 mg/ml, 0.06 mg/ml, 0.03 mg/ml, 0.015 mg/ml, 0.0076 mg/ml, 0.0034 mg/ml and 0.0019 mg/ml). The toxicity and teratogenicity of the mud on zebrafish embryos were assessed every 24 hours, for 96 hours, using endpoints like embryo mortality, heart rate and hatching rate. Results: The heavy metal content of used OBDMs had the highest concentration of barium (Ba) 2360 ppm, followed by lead (Pb) 120 ppm, zinc (Zn) 104 ppm, arsenic (As) 9 ppm, and chromium (Cr) 16 ppm, with cadmium (Cd) concentration of less than 1 ppm being the lowest. The Ba (2360 mg/L) concentration in the OBDM sample exceeded the concentration of Ba in normal marine sediment reported to be around 2000 mg/L. The 96 h LC50 of the OBDM in zebrafish embryos was reported to be 0.005 mg/mL (5 ppm). Zebrafish embryos that were exposed to high concentrations of OBDMs exhibited a lower hatching rate and reduced heart rate than the control group. Conclusion: The findings of this study are indicative of the highly toxic nature of used OBDMs and its dosage-dependent teratogenicity effects on zebrafish embryo. Knowledge of the potential environmental impacts of OBDMs released into the marine environment can be the basis for prudent decision-making that will help minimize environmental damage.
{"title":"Heavy Metal Content Analysis and Toxicity Assessment of Oil-Based Drilling Mud using Zebrafish Embryos","authors":"N. Sridewi, Siti Nurbariah, Syahida Ahmad","doi":"10.7225/toms.v10.n02.w06","DOIUrl":"https://doi.org/10.7225/toms.v10.n02.w06","url":null,"abstract":"Aim: Used oil-based drilling muds (OBDMs) are toxic to marine organisms due to the fluid’s complex chemical nature. The illegal dumping of used OBDMs is still rampant in many parts of the world despite of the stringent laws and regulations pertaining to its disposal. To date, study of the assessment of heavy metal content in used OBDMs from the Malaysian oil and gas industry has been limited. Furthermore, the study of the toxic effect of OBDMs using a zebrafish embryo model has never been reported before. Therefore, in this research, the used oil-based drilling muds (OBDMs) were analyzed for their heavy metal content and toxicity against Zebrafish embryos. Methods: Used OBDMs were collected from an Anchor Handling Tug Supply (AHTS) vessel mud tank from Kemaman, Terengganu. The heavy metal content in the mud was analyzed using ICP-AES. Zebrafish embryos were exposed to OBDMs of varying concentrations (i.e., 0.25 mg/ml, 0.125 mg/ml, 0.06 mg/ml, 0.03 mg/ml, 0.015 mg/ml, 0.0076 mg/ml, 0.0034 mg/ml and 0.0019 mg/ml). The toxicity and teratogenicity of the mud on zebrafish embryos were assessed every 24 hours, for 96 hours, using endpoints like embryo mortality, heart rate and hatching rate. Results: The heavy metal content of used OBDMs had the highest concentration of barium (Ba) 2360 ppm, followed by lead (Pb) 120 ppm, zinc (Zn) 104 ppm, arsenic (As) 9 ppm, and chromium (Cr) 16 ppm, with cadmium (Cd) concentration of less than 1 ppm being the lowest. The Ba (2360 mg/L) concentration in the OBDM sample exceeded the concentration of Ba in normal marine sediment reported to be around 2000 mg/L. The 96 h LC50 of the OBDM in zebrafish embryos was reported to be 0.005 mg/mL (5 ppm). Zebrafish embryos that were exposed to high concentrations of OBDMs exhibited a lower hatching rate and reduced heart rate than the control group. Conclusion: The findings of this study are indicative of the highly toxic nature of used OBDMs and its dosage-dependent teratogenicity effects on zebrafish embryo. Knowledge of the potential environmental impacts of OBDMs released into the marine environment can be the basis for prudent decision-making that will help minimize environmental damage.","PeriodicalId":42576,"journal":{"name":"Transactions on Maritime Science-ToMS","volume":"118 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77391256","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 : 2021-10-21DOI: 10.7225/toms.v10.n02.004
Sarah Isnan, Nur Hazimah Nordin, A. Rahman, Afiqah Rosly, A. Aziz, Zulkifly Mat Radzi, Abu Zarim, Muhammad Syafiq Bin Mohd Abu
Statistics from the Marine Department in Malaysian Territorial waters has shown an increase in maritime accidents. The data of maritime accidents, including latitude and longitude of the locations, are analysed using Geographical Information System with Kernel Density function. This is to visualise, locate and identify the high-risk location of maritime accidents in Malaysian waters. Using the GIS analysis, the findings suggest that the data of the high-risk maritime location is at Malacca Straits. The results showed that GIS analysis is a useful tool to analyse maritime accidents data and can be used as a guidance for navigators to plan their passage in order to avoid maritime accidents.
{"title":"Application of GIS: Maritime Accident Analysis in Malaysian Waters Using Kernel Density Function","authors":"Sarah Isnan, Nur Hazimah Nordin, A. Rahman, Afiqah Rosly, A. Aziz, Zulkifly Mat Radzi, Abu Zarim, Muhammad Syafiq Bin Mohd Abu","doi":"10.7225/toms.v10.n02.004","DOIUrl":"https://doi.org/10.7225/toms.v10.n02.004","url":null,"abstract":"Statistics from the Marine Department in Malaysian Territorial waters has shown an increase in maritime accidents. The data of maritime accidents, including latitude and longitude of the locations, are analysed using Geographical Information System with Kernel Density function. This is to visualise, locate and identify the high-risk location of maritime accidents in Malaysian waters. Using the GIS analysis, the findings suggest that the data of the high-risk maritime location is at Malacca Straits. The results showed that GIS analysis is a useful tool to analyse maritime accidents data and can be used as a guidance for navigators to plan their passage in order to avoid maritime accidents.\u0000 ","PeriodicalId":42576,"journal":{"name":"Transactions on Maritime Science-ToMS","volume":"127 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91357385","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 : 2021-10-21DOI: 10.7225/toms.v10.n02.014
Farizha Ibrahim, Mohd Norsyarizad Razali, Noh Zainal Abidin
Human-related factors account for more than 80% of accidents at sea, based on studies. According to Global Claims Review 2017 released by Allianz Global Corporate & Specialty, an estimated 75-96% of shipping accidents have a high probability of involving human error (AGCS, 2017). Designs that do not meet human factors' needs play a significant role in contributing to human error. Documents in terms of design standards and guidelines, rules, and laws are analyzed. As a result, several documents related to human factors have been identified. These documents are based on whether to implement it, even if some are prescriptive, and others are mandatory, being published at different enforcement levels. In ensuring the consistent implementation of human factors, regulators and authorities need to take stricter measures in all the processes involved in designing and building such ships.
{"title":"Content Analysis of International Standards for Human Factors in Ship Design and Operation","authors":"Farizha Ibrahim, Mohd Norsyarizad Razali, Noh Zainal Abidin","doi":"10.7225/toms.v10.n02.014","DOIUrl":"https://doi.org/10.7225/toms.v10.n02.014","url":null,"abstract":"Human-related factors account for more than 80% of accidents at sea, based on studies. According to Global Claims Review 2017 released by Allianz Global Corporate & Specialty, an estimated 75-96% of shipping accidents have a high probability of involving human error (AGCS, 2017). Designs that do not meet human factors' needs play a significant role in contributing to human error. Documents in terms of design standards and guidelines, rules, and laws are analyzed. As a result, several documents related to human factors have been identified. These documents are based on whether to implement it, even if some are prescriptive, and others are mandatory, being published at different enforcement levels. In ensuring the consistent implementation of human factors, regulators and authorities need to take stricter measures in all the processes involved in designing and building such ships.","PeriodicalId":42576,"journal":{"name":"Transactions on Maritime Science-ToMS","volume":"14 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85332145","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 : 2021-10-21DOI: 10.7225/toms.v10.n02.019
R. R. Kolombatović, Rea Barbir, Petricija Knežić, Marko Maretić, Katarina Stegić, Dolores Štefanac, Ž. Bašić, I. Kružić
This research has examined the attitudes and perceptions of tourists that visited the Republic of Croatia (RH) during the summer of 2019 about the perception of safety in RH, especially on general security, as well as food safety, personal safety, epidemic safety, and natural disasters. Also, we have examined the confidence in Croatian services, such as the police, rescue services, medical emergency, etc. Almost all the safety components were above 4, which indicates that the tourists in Croatia feel safe and trust the services. This research could be a significant tool for improving the policies for attracting the tourists during and after the pandemic.
{"title":"Tourist's Perception of Safety in the Republic of Croatia in 2019","authors":"R. R. Kolombatović, Rea Barbir, Petricija Knežić, Marko Maretić, Katarina Stegić, Dolores Štefanac, Ž. Bašić, I. Kružić","doi":"10.7225/toms.v10.n02.019","DOIUrl":"https://doi.org/10.7225/toms.v10.n02.019","url":null,"abstract":"This research has examined the attitudes and perceptions of tourists that visited the Republic of Croatia (RH) during the summer of 2019 about the perception of safety in RH, especially on general security, as well as food safety, personal safety, epidemic safety, and natural disasters. Also, we have examined the confidence in Croatian services, such as the police, rescue services, medical emergency, etc. Almost all the safety components were above 4, which indicates that the tourists in Croatia feel safe and trust the services. This research could be a significant tool for improving the policies for attracting the tourists during and after the pandemic.","PeriodicalId":42576,"journal":{"name":"Transactions on Maritime Science-ToMS","volume":"93 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85467351","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 : 2021-10-21DOI: 10.7225/toms.v10.n02.w08
Andrej Androjna, M. Perkovič
The development of contemporary navigation and positioning systems have significantly improved reliability and speeds in maritime navigation. At the same time, the vulnerabilities of these systems to cyber threats represent a remarkable issue to the safety of navigation. Therefore, the maritime community has raised the question of cybersecurity of navigation systems in recent years. This paper aims to analyse the vulnerabilities of the Global Navigation Satellite System (GNSS), Electronic Chart Display Information System (ECDIS) and Automatic Identification System (AIS). The concepts of these systems were developed at a time when cybersecurity issues have not been among the top priorities. Open broadcasts, the absence of or limited existence of data encryption and authentication can be considered as their primary security weaknesses. Therefore, these systems are vulnerable to cyber-attacks. The GPS as the data source of a ship’s position can relatively easily be jammed and/or spoofed, increasing the vulnerabilities of ECDIS and AIS. A systematic literature review was conducted for this article, supplemented by a SWOT analysis of the AIS service and particular case studies of recent cyber-attacks on these systems. The analysis of selected case studies confirmed that these systems could easily be spoofed and become a subject of data manipulation with significant consequences for the safety of navigation. The paper provides conclusions and recommendations highlighting the necessity for the users to be aware of the vulnerabilities of modern navigation systems.
{"title":"Impact of Spoofing of Navigation Systems on Maritime Situational Awareness","authors":"Andrej Androjna, M. Perkovič","doi":"10.7225/toms.v10.n02.w08","DOIUrl":"https://doi.org/10.7225/toms.v10.n02.w08","url":null,"abstract":"The development of contemporary navigation and positioning systems have significantly improved reliability and speeds in maritime navigation. At the same time, the vulnerabilities of these systems to cyber threats represent a remarkable issue to the safety of navigation. Therefore, the maritime community has raised the question of cybersecurity of navigation systems in recent years. This paper aims to analyse the vulnerabilities of the Global Navigation Satellite System (GNSS), Electronic Chart Display Information System (ECDIS) and Automatic Identification System (AIS). The concepts of these systems were developed at a time when cybersecurity issues have not been among the top priorities. Open broadcasts, the absence of or limited existence of data encryption and authentication can be considered as their primary security weaknesses. Therefore, these systems are vulnerable to cyber-attacks. The GPS as the data source of a ship’s position can relatively easily be jammed and/or spoofed, increasing the vulnerabilities of ECDIS and AIS. A systematic literature review was conducted for this article, supplemented by a SWOT analysis of the AIS service and particular case studies of recent cyber-attacks on these systems. The analysis of selected case studies confirmed that these systems could easily be spoofed and become a subject of data manipulation with significant consequences for the safety of navigation. The paper provides conclusions and recommendations highlighting the necessity for the users to be aware of the vulnerabilities of modern navigation systems.","PeriodicalId":42576,"journal":{"name":"Transactions on Maritime Science-ToMS","volume":"27 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78148808","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 : 2021-10-21DOI: 10.7225/toms.v10.n02.w07
Ana Kuzmanić Skelin, Lea Vojković, Dani Mohović, D. Zec
Probabilistic maritime accident models based on Bayesian Networks are typically built upon the data available in accident records and the data obtained from human experts knowledge on accident. The drawback of such models is that they do not take explicitly into the account the knowledge on non-accidents as would be required in the probabilistic modelling of rare events. Consequently, these models have difficulties with delivering interpretation of influence of risk factors and providing sufficient confidence in the risk assessment scores. In this work, modelling and risk score interpretation, as two aspects of the probabilistic approach to complex maritime system risk assessment, are addressed. First, the maritime accident modelling is posed as a classification problem and the Bayesian network classifier that discriminates between accident and non-accident is developed which assesses state spaces of influence factors as the input features of the classifier. Maritime accident risk are identified as adversely influencing factors that contribute to the accident. Next, the weight of evidence approach to reasoning with Bayesian network classifier is developed for an objective quantitative estimation of the strength of factor influence, and a weighted strength of evidence is introduced. Qualitative interpretation of strength of evidence for individual accident influencing factor, inspired by Bayes factor, is defined. The efficiency of the developed approach is demonstrated within the context of collision of small passenger vessels and the results of collision risk assessments are given for the environmental settings typical in Croatian nautical tourism. According to the results obtained, recommendations for navigation safety during high density traffic have been distilled.
{"title":"Weight of Evidence Approach to Maritime Accident Risk Assessment Based on Bayesian Network Classifier","authors":"Ana Kuzmanić Skelin, Lea Vojković, Dani Mohović, D. Zec","doi":"10.7225/toms.v10.n02.w07","DOIUrl":"https://doi.org/10.7225/toms.v10.n02.w07","url":null,"abstract":"Probabilistic maritime accident models based on Bayesian Networks are typically built upon the data available in accident records and the data obtained from human experts knowledge on accident. The drawback of such models is that they do not take explicitly into the account the knowledge on non-accidents as would be required in the probabilistic modelling of rare events. Consequently, these models have difficulties with delivering interpretation of influence of risk factors and providing sufficient confidence in the risk assessment scores. In this work, modelling and risk score interpretation, as two aspects of the probabilistic approach to complex maritime system risk assessment, are addressed. First, the maritime accident modelling is posed as a classification problem and the Bayesian network classifier that discriminates between accident and non-accident is developed which assesses state spaces of influence factors as the input features of the classifier. Maritime accident risk are identified as adversely influencing factors that contribute to the accident. Next, the weight of evidence approach to reasoning with Bayesian network classifier is developed for an objective quantitative estimation of the strength of factor influence, and a weighted strength of evidence is introduced. Qualitative interpretation of strength of evidence for individual accident influencing factor, inspired by Bayes factor, is defined. The efficiency of the developed approach is demonstrated within the context of collision of small passenger vessels and the results of collision risk assessments are given for the environmental settings typical in Croatian nautical tourism. According to the results obtained, recommendations for navigation safety during high density traffic have been distilled.","PeriodicalId":42576,"journal":{"name":"Transactions on Maritime Science-ToMS","volume":"23 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74432377","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 : 2021-10-21DOI: 10.7225/toms.v10.n02.w04
Bangar Raju Totakura, Vrinda Sharma, Vishal Kashav, Subir Ranjan Das
Aim: The main objective of this paper is to explore the volatility of ship demolition indices. Ship demolition indices are becoming increasingly important owing to the growing number of norms and rules imposed by the International Maritime Organization. Financial crunch and stricter emission norms are forcing vessel owners to consider ship demolition options. This study examines the volatility of ship demolition rates of the Baltic Demolition Index and the causal relationship between the Chinese and Indian subcontinent indices. Methods: EGARCH models have been used to explore the volatility and asymmetric effects in the time series. The relationship between the two indices was established using the Granger causality test. Results and conclusion: The final analysis confirmed that ship demolition indices are both volatile and asymmetric. This study is unique and useful to ship owners, vessel operators, and banks as it helps them understand the risks involved.
{"title":"Volatility of Ship Demolition Index Prices","authors":"Bangar Raju Totakura, Vrinda Sharma, Vishal Kashav, Subir Ranjan Das","doi":"10.7225/toms.v10.n02.w04","DOIUrl":"https://doi.org/10.7225/toms.v10.n02.w04","url":null,"abstract":"Aim: The main objective of this paper is to explore the volatility of ship demolition indices. Ship demolition indices are becoming increasingly important owing to the growing number of norms and rules imposed by the International Maritime Organization. Financial crunch and stricter emission norms are forcing vessel owners to consider ship demolition options. This study examines the volatility of ship demolition rates of the Baltic Demolition Index and the causal relationship between the Chinese and Indian subcontinent indices. Methods: EGARCH models have been used to explore the volatility and asymmetric effects in the time series. The relationship between the two indices was established using the Granger causality test. Results and conclusion: The final analysis confirmed that ship demolition indices are both volatile and asymmetric. This study is unique and useful to ship owners, vessel operators, and banks as it helps them understand the risks involved.","PeriodicalId":42576,"journal":{"name":"Transactions on Maritime Science-ToMS","volume":"159 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91384179","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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