Zeyang Liu, Yiqun Liu, K. Zhou, Min Zhang, Shaoping Ma
Research in how users examine results on search engine result pages (SERPs) helps improve result ranking, advertisement placement, performance evaluation and search UI design. Although examination behavior on organic search results (also known as "ten blue links") has been well studied in existing works, there lacks a thorough investigation on how users examine SERPs with verticals. Considering the fact that a large fraction of SERPs are served with one or more verticals in the practical Web search scenario, it is of vital importance to understand the influence of vertical results on search examination behaviors. In this paper, we focus on five popular vertical types and try to study their influences on users' examination processes in both cases when they are relevant or irrelevant to the search queries. With examination behavior data collected with an eye-tracking device, we show the existence of vertical-aware user behavior effects including vertical attraction effect, examination cut-off effect in the presence of a relevant vertical, and examination spill-over effect in the presence of an irrelevant vertical. Furthermore, we are also among the first to systematically investigate the internal examination behavior within the vertical results. We believe that this work will promote our understanding of user interactions with federated search engines and bring benefit to the construction of search performance evaluations.
{"title":"Influence of Vertical Result in Web Search Examination","authors":"Zeyang Liu, Yiqun Liu, K. Zhou, Min Zhang, Shaoping Ma","doi":"10.1145/2766462.2767714","DOIUrl":"https://doi.org/10.1145/2766462.2767714","url":null,"abstract":"Research in how users examine results on search engine result pages (SERPs) helps improve result ranking, advertisement placement, performance evaluation and search UI design. Although examination behavior on organic search results (also known as \"ten blue links\") has been well studied in existing works, there lacks a thorough investigation on how users examine SERPs with verticals. Considering the fact that a large fraction of SERPs are served with one or more verticals in the practical Web search scenario, it is of vital importance to understand the influence of vertical results on search examination behaviors. In this paper, we focus on five popular vertical types and try to study their influences on users' examination processes in both cases when they are relevant or irrelevant to the search queries. With examination behavior data collected with an eye-tracking device, we show the existence of vertical-aware user behavior effects including vertical attraction effect, examination cut-off effect in the presence of a relevant vertical, and examination spill-over effect in the presence of an irrelevant vertical. Furthermore, we are also among the first to systematically investigate the internal examination behavior within the vertical results. We believe that this work will promote our understanding of user interactions with federated search engines and bring benefit to the construction of search performance evaluations.","PeriodicalId":297035,"journal":{"name":"Proceedings of the 38th International ACM SIGIR Conference on Research and Development in Information Retrieval","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122152929","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}
Lina Yao, Quan Z. Sheng, Yongrui Qin, Xianzhi Wang, A. Shemshadi, Qi He
Point-of-Interest (POI) recommendation is a new type of recommendation task that comes along with the prevalence of location-based social networks in recent years. Compared with traditional tasks, it focuses more on personalized, context-aware recommendation results to provide better user experience. To address this new challenge, we propose a Collaborative Filtering method based on Non-negative Tensor Factorization, a generalization of the Matrix Factorization approach that exploits a high-order tensor instead of traditional User-Location matrix to model multi-dimensional contextual information. The factorization of this tensor leads to a compact model of the data which is specially suitable for context-aware POI recommendations. In addition, we fuse users' social relations as regularization terms of the factorization to improve the recommendation accuracy. Experimental results on real-world datasets demonstrate the effectiveness of our approach.
{"title":"Context-aware Point-of-Interest Recommendation Using Tensor Factorization with Social Regularization","authors":"Lina Yao, Quan Z. Sheng, Yongrui Qin, Xianzhi Wang, A. Shemshadi, Qi He","doi":"10.1145/2766462.2767794","DOIUrl":"https://doi.org/10.1145/2766462.2767794","url":null,"abstract":"Point-of-Interest (POI) recommendation is a new type of recommendation task that comes along with the prevalence of location-based social networks in recent years. Compared with traditional tasks, it focuses more on personalized, context-aware recommendation results to provide better user experience. To address this new challenge, we propose a Collaborative Filtering method based on Non-negative Tensor Factorization, a generalization of the Matrix Factorization approach that exploits a high-order tensor instead of traditional User-Location matrix to model multi-dimensional contextual information. The factorization of this tensor leads to a compact model of the data which is specially suitable for context-aware POI recommendations. In addition, we fuse users' social relations as regularization terms of the factorization to improve the recommendation accuracy. Experimental results on real-world datasets demonstrate the effectiveness of our approach.","PeriodicalId":297035,"journal":{"name":"Proceedings of the 38th International ACM SIGIR Conference on Research and Development in Information Retrieval","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125872995","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}
When searching for place entities such as businesses or points of interest, the desired place may be close (finding the nearest ATM) or far away (finding a hotel in another city). Understanding the role of distance in predicting user interests can guide the design of location search and recommendation systems. We analyze a large dataset of location searches on GPS-enabled mobile devices with 15 location categories. We model user-location distance based on raw geographic distance (kilometers) and intervening opportunities (nth closest). Both models are helpful in predicting user interests, with the intervening opportunity model performing somewhat better. We find significant inter-category variation. For instance, the closest movie theater is selected in 17.7% of cases, while the closest restaurant in only 2.1% of cases. Overall, we recommend taking category information into account when modeling location preferences of users in search and recommendation systems.
{"title":"Inter-Category Variation in Location Search","authors":"Chia-Jung Lee, Nick Craswell, Vanessa Murdock","doi":"10.1145/2766462.2767797","DOIUrl":"https://doi.org/10.1145/2766462.2767797","url":null,"abstract":"When searching for place entities such as businesses or points of interest, the desired place may be close (finding the nearest ATM) or far away (finding a hotel in another city). Understanding the role of distance in predicting user interests can guide the design of location search and recommendation systems. We analyze a large dataset of location searches on GPS-enabled mobile devices with 15 location categories. We model user-location distance based on raw geographic distance (kilometers) and intervening opportunities (nth closest). Both models are helpful in predicting user interests, with the intervening opportunity model performing somewhat better. We find significant inter-category variation. For instance, the closest movie theater is selected in 17.7% of cases, while the closest restaurant in only 2.1% of cases. Overall, we recommend taking category information into account when modeling location preferences of users in search and recommendation systems.","PeriodicalId":297035,"journal":{"name":"Proceedings of the 38th International ACM SIGIR Conference on Research and Development in Information Retrieval","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129493213","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}
Adam Roegiest, G. Cormack, C. Clarke, Maura R. Grossman
We are concerned with the effect of using a surrogate assessor to train a passive (i.e., batch) supervised-learning method to rank documents for subsequent review, where the effectiveness of the ranking will be evaluated using a different assessor deemed to be authoritative. Previous studies suggest that surrogate assessments may be a reasonable proxy for authoritative assessments for this task. Nonetheless, concern persists in some application domains---such as electronic discovery---that errors in surrogate training assessments will be amplified by the learning method, materially degrading performance. We demonstrate, through a re-analysis of data used in previous studies, that, with passive supervised-learning methods, using surrogate assessments for training can substantially impair classifier performance, relative to using the same deemed-authoritative assessor for both training and assessment. In particular, using a single surrogate to replace the authoritative assessor for training often yields a ranking that must be traversed much lower to achieve the same level of recall as the ranking that would have resulted had the authoritative assessor been used for training. We also show that steps can be taken to mitigate, and sometimes overcome, the impact of surrogate assessments for training: relevance assessments may be diversified through the use of multiple surrogates; and, a more liberal view of relevance can be adopted by having the surrogate label borderline documents as relevant. By taking these steps, rankings derived from surrogate assessments can match, and sometimes exceed, the performance of the ranking that would have been achieved, had the authority been used for training. Finally, we show that our results still hold when the role of surrogate and authority are interchanged, indicating that the results may simply reflect differing conceptions of relevance between surrogate and authority, as opposed to the authority having special skill or knowledge lacked by the surrogate.
{"title":"Impact of Surrogate Assessments on High-Recall Retrieval","authors":"Adam Roegiest, G. Cormack, C. Clarke, Maura R. Grossman","doi":"10.1145/2766462.2767754","DOIUrl":"https://doi.org/10.1145/2766462.2767754","url":null,"abstract":"We are concerned with the effect of using a surrogate assessor to train a passive (i.e., batch) supervised-learning method to rank documents for subsequent review, where the effectiveness of the ranking will be evaluated using a different assessor deemed to be authoritative. Previous studies suggest that surrogate assessments may be a reasonable proxy for authoritative assessments for this task. Nonetheless, concern persists in some application domains---such as electronic discovery---that errors in surrogate training assessments will be amplified by the learning method, materially degrading performance. We demonstrate, through a re-analysis of data used in previous studies, that, with passive supervised-learning methods, using surrogate assessments for training can substantially impair classifier performance, relative to using the same deemed-authoritative assessor for both training and assessment. In particular, using a single surrogate to replace the authoritative assessor for training often yields a ranking that must be traversed much lower to achieve the same level of recall as the ranking that would have resulted had the authoritative assessor been used for training. We also show that steps can be taken to mitigate, and sometimes overcome, the impact of surrogate assessments for training: relevance assessments may be diversified through the use of multiple surrogates; and, a more liberal view of relevance can be adopted by having the surrogate label borderline documents as relevant. By taking these steps, rankings derived from surrogate assessments can match, and sometimes exceed, the performance of the ranking that would have been achieved, had the authority been used for training. Finally, we show that our results still hold when the role of surrogate and authority are interchanged, indicating that the results may simply reflect differing conceptions of relevance between surrogate and authority, as opposed to the authority having special skill or knowledge lacked by the surrogate.","PeriodicalId":297035,"journal":{"name":"Proceedings of the 38th International ACM SIGIR Conference on Research and Development in Information Retrieval","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129488819","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}
Anne Schuth, Robert-Jan Bruintjes, Fritjof Buüttner, J. Doorn, C. Groenland, Harrie Oosterhuis, Cong-Nguyen Tran, Bastiaan S. Veeling, Jos van der Velde, R. Wechsler, David Woudenberg, M. de Rijke
Online evaluation methods for information retrieval use implicit signals such as clicks from users to infer preferences between rankers. A highly sensitive way of inferring these preferences is through interleaved comparisons. Recently, interleaved comparisons methods that allow for simultaneous evaluation of more than two rankers have been introduced. These so-called multileaving methods are even more sensitive than their interleaving counterparts. Probabilistic interleaving--whose main selling point is the potential for reuse of historical data--has no multileaving counterpart yet. We propose probabilistic multileave and empirically show that it is highly sensitive and unbiased. An important implication of this result is that historical interactions with multileaved comparisons can be reused, allowing for ranker comparisons that need much less user interaction data. Furthermore, we show that our method, as opposed to earlier sensitive multileaving methods, scales well when the number of rankers increases.
{"title":"Probabilistic Multileave for Online Retrieval Evaluation","authors":"Anne Schuth, Robert-Jan Bruintjes, Fritjof Buüttner, J. Doorn, C. Groenland, Harrie Oosterhuis, Cong-Nguyen Tran, Bastiaan S. Veeling, Jos van der Velde, R. Wechsler, David Woudenberg, M. de Rijke","doi":"10.1145/2766462.2767838","DOIUrl":"https://doi.org/10.1145/2766462.2767838","url":null,"abstract":"Online evaluation methods for information retrieval use implicit signals such as clicks from users to infer preferences between rankers. A highly sensitive way of inferring these preferences is through interleaved comparisons. Recently, interleaved comparisons methods that allow for simultaneous evaluation of more than two rankers have been introduced. These so-called multileaving methods are even more sensitive than their interleaving counterparts. Probabilistic interleaving--whose main selling point is the potential for reuse of historical data--has no multileaving counterpart yet. We propose probabilistic multileave and empirically show that it is highly sensitive and unbiased. An important implication of this result is that historical interactions with multileaved comparisons can be reused, allowing for ranker comparisons that need much less user interaction data. Furthermore, we show that our method, as opposed to earlier sensitive multileaving methods, scales well when the number of rankers increases.","PeriodicalId":297035,"journal":{"name":"Proceedings of the 38th International ACM SIGIR Conference on Research and Development in Information Retrieval","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128231587","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}
Selective distributed search is a retrieval architecture that reduces search costs by partitioning a corpus into topical shards such that only a few shards need to be searched for each query. Prior research created topical shards by using random seed documents to cluster a random sample of the full corpus. The resource selection algorithm might use a different random sample of the corpus. These random components make selective search non-deterministic. This paper studies how these random components affect experimental results. Experiments on two ClueWeb09 corpora and four query sets show that in spite of random components, selective search is stable for most queries.
{"title":"How Random Decisions Affect Selective Distributed Search","authors":"Zhuyun Dai, Yubin Kim, James P. Callan","doi":"10.1145/2766462.2767796","DOIUrl":"https://doi.org/10.1145/2766462.2767796","url":null,"abstract":"Selective distributed search is a retrieval architecture that reduces search costs by partitioning a corpus into topical shards such that only a few shards need to be searched for each query. Prior research created topical shards by using random seed documents to cluster a random sample of the full corpus. The resource selection algorithm might use a different random sample of the corpus. These random components make selective search non-deterministic. This paper studies how these random components affect experimental results. Experiments on two ClueWeb09 corpora and four query sets show that in spite of random components, selective search is stable for most queries.","PeriodicalId":297035,"journal":{"name":"Proceedings of the 38th International ACM SIGIR Conference on Research and Development in Information Retrieval","volume":"48 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131478051","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}
Recommending users with their preferred points-of-interest (POIs), e.g., museums and restaurants, has become an important feature for location-based social networks (LBSNs), which benefits people to explore new places and businesses to discover potential customers. However, because users only check in a few POIs in an LBSN, the user-POI check-in interaction is highly sparse, which renders a big challenge for POI recommendations. To tackle this challenge, in this study we propose a new POI recommendation approach called GeoSoCa through exploiting geographical correlations, social correlations and categorical correlations among users and POIs. The geographical, social and categorical correlations can be learned from the historical check-in data of users on POIs and utilized to predict the relevance score of a user to an unvisited POI so as to make recommendations for users. First, in GeoSoCa we propose a kernel estimation method with an adaptive bandwidth to determine a personalized check-in distribution of POIs for each user that naturally models the geographical correlations between POIs. Then, GeoSoCa aggregates the check-in frequency or rating of a user's friends on a POI and models the social check-in frequency or rating as a power-law distribution to employ the social correlations between users. Further, GeoSoCa applies the bias of a user on a POI category to weigh the popularity of a POI in the corresponding category and models the weighed popularity as a power-law distribution to leverage the categorical correlations between POIs. Finally, we conduct a comprehensive performance evaluation for GeoSoCa using two large-scale real-world check-in data sets collected from Foursquare and Yelp. Experimental results show that GeoSoCa achieves significantly superior recommendation quality compared to other state-of-the-art POI recommendation techniques.
{"title":"GeoSoCa: Exploiting Geographical, Social and Categorical Correlations for Point-of-Interest Recommendations","authors":"Jiadong Zhang, Chi-Yin Chow","doi":"10.1145/2766462.2767711","DOIUrl":"https://doi.org/10.1145/2766462.2767711","url":null,"abstract":"Recommending users with their preferred points-of-interest (POIs), e.g., museums and restaurants, has become an important feature for location-based social networks (LBSNs), which benefits people to explore new places and businesses to discover potential customers. However, because users only check in a few POIs in an LBSN, the user-POI check-in interaction is highly sparse, which renders a big challenge for POI recommendations. To tackle this challenge, in this study we propose a new POI recommendation approach called GeoSoCa through exploiting geographical correlations, social correlations and categorical correlations among users and POIs. The geographical, social and categorical correlations can be learned from the historical check-in data of users on POIs and utilized to predict the relevance score of a user to an unvisited POI so as to make recommendations for users. First, in GeoSoCa we propose a kernel estimation method with an adaptive bandwidth to determine a personalized check-in distribution of POIs for each user that naturally models the geographical correlations between POIs. Then, GeoSoCa aggregates the check-in frequency or rating of a user's friends on a POI and models the social check-in frequency or rating as a power-law distribution to employ the social correlations between users. Further, GeoSoCa applies the bias of a user on a POI category to weigh the popularity of a POI in the corresponding category and models the weighed popularity as a power-law distribution to leverage the categorical correlations between POIs. Finally, we conduct a comprehensive performance evaluation for GeoSoCa using two large-scale real-world check-in data sets collected from Foursquare and Yelp. Experimental results show that GeoSoCa achieves significantly superior recommendation quality compared to other state-of-the-art POI recommendation techniques.","PeriodicalId":297035,"journal":{"name":"Proceedings of the 38th International ACM SIGIR Conference on Research and Development in Information Retrieval","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131506676","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}
Sérgio D. Canuto, Marcos André Gonçalves, W. M. D. Santos, Thierson Couto, W. Martins
The unprecedented growth of available data nowadays has stimulated the development of new methods for organizing and extracting useful knowledge from this immense amount of data. Automatic Document Classification (ADC) is one of such methods, that uses machine learning techniques to build models capable of automatically associating documents to well-defined semantic classes. ADC is the basis of many important applications such as language identification, sentiment analysis, recommender systems, spam filtering, among others. Recently, the use of meta-features has been shown to substantially improve the effectiveness of ADC algorithms. In particular, the use of meta-features that make a combined use of local information (through kNN-based features) and global information (through category centroids) has produced promising results. However, the generation of these meta-features is very costly in terms of both, memory consumption and runtime since there is the need to constantly call the kNN algorithm. We take advantage of the current manycore GPU architecture and present a massively parallel version of the kNN algorithm for highly dimensional and sparse datasets (which is the case for ADC). Our experimental results show that we can obtain speedup gains of up to 15x while reducing memory consumption in more than 5000x when compared to a state-of-the-art parallel baseline. This opens up the possibility of applying meta-features based classification in large collections of documents, that would otherwise take too much time or require the use of an expensive computational platform.
{"title":"An Efficient and Scalable MetaFeature-based Document Classification Approach based on Massively Parallel Computing","authors":"Sérgio D. Canuto, Marcos André Gonçalves, W. M. D. Santos, Thierson Couto, W. Martins","doi":"10.1145/2766462.2767743","DOIUrl":"https://doi.org/10.1145/2766462.2767743","url":null,"abstract":"The unprecedented growth of available data nowadays has stimulated the development of new methods for organizing and extracting useful knowledge from this immense amount of data. Automatic Document Classification (ADC) is one of such methods, that uses machine learning techniques to build models capable of automatically associating documents to well-defined semantic classes. ADC is the basis of many important applications such as language identification, sentiment analysis, recommender systems, spam filtering, among others. Recently, the use of meta-features has been shown to substantially improve the effectiveness of ADC algorithms. In particular, the use of meta-features that make a combined use of local information (through kNN-based features) and global information (through category centroids) has produced promising results. However, the generation of these meta-features is very costly in terms of both, memory consumption and runtime since there is the need to constantly call the kNN algorithm. We take advantage of the current manycore GPU architecture and present a massively parallel version of the kNN algorithm for highly dimensional and sparse datasets (which is the case for ADC). Our experimental results show that we can obtain speedup gains of up to 15x while reducing memory consumption in more than 5000x when compared to a state-of-the-art parallel baseline. This opens up the possibility of applying meta-features based classification in large collections of documents, that would otherwise take too much time or require the use of an expensive computational platform.","PeriodicalId":297035,"journal":{"name":"Proceedings of the 38th International ACM SIGIR Conference on Research and Development in Information Retrieval","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128732551","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}
Web search engine companies require power-hungry data centers with thousands of servers to efficiently perform searches on a large scale. This permits the search engines to serve high arrival rates of user queries with low latency, but poses economical and environmental concerns due to the power consumption of the servers. Existing power saving techniques sacrifice the raw performance of a server for reduced power absorption, by scaling the frequency of the server's CPU according to its utilization. For instance, current Linux kernels include frequency governors i.e., mechanisms designed to dynamically throttle the CPU operational frequency. However, such general-domain techniques work at the operating system level and have no knowledge about the querying operations of the server. In this work, we propose to delegate CPU power management to search engine-specific governors. These can leverage knowledge coming from the querying operations, such as the query server utilization and load. By exploiting such additional knowledge, we can appropriately throttle the CPU frequency thereby reducing the query server power consumption. Experiments are conducted upon the TREC ClueWeb09 corpus and the query stream from the MSN 2006 query log. Results show that we can reduce up to ~24% a server power consumption, with only limited drawbacks in effectiveness w.r.t. a system running at maximum CPU frequency to promote query processing quality.
{"title":"Load-sensitive CPU Power Management for Web Search Engines","authors":"Matteo Catena, C. Macdonald, N. Tonellotto","doi":"10.1145/2766462.2767809","DOIUrl":"https://doi.org/10.1145/2766462.2767809","url":null,"abstract":"Web search engine companies require power-hungry data centers with thousands of servers to efficiently perform searches on a large scale. This permits the search engines to serve high arrival rates of user queries with low latency, but poses economical and environmental concerns due to the power consumption of the servers. Existing power saving techniques sacrifice the raw performance of a server for reduced power absorption, by scaling the frequency of the server's CPU according to its utilization. For instance, current Linux kernels include frequency governors i.e., mechanisms designed to dynamically throttle the CPU operational frequency. However, such general-domain techniques work at the operating system level and have no knowledge about the querying operations of the server. In this work, we propose to delegate CPU power management to search engine-specific governors. These can leverage knowledge coming from the querying operations, such as the query server utilization and load. By exploiting such additional knowledge, we can appropriately throttle the CPU frequency thereby reducing the query server power consumption. Experiments are conducted upon the TREC ClueWeb09 corpus and the query stream from the MSN 2006 query log. Results show that we can reduce up to ~24% a server power consumption, with only limited drawbacks in effectiveness w.r.t. a system running at maximum CPU frequency to promote query processing quality.","PeriodicalId":297035,"journal":{"name":"Proceedings of the 38th International ACM SIGIR Conference on Research and Development in Information Retrieval","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128829373","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}
Giovanni Di Santo, R. McCreadie, C. Macdonald, I. Ounis
Within a search engine, query auto-completion aims to predict the final query the user wants to enter as they type, with the aim of reducing query entry time and potentially preparing the search results in advance of query submission. There are a large number of approaches to automatically rank candidate queries for the purposes of auto-completion. However, no study exists that compares these approaches on a single dataset. Hence, in this paper, we present a comparison study between current approaches to rank candidate query completions for the user query as it is typed. Using a query-log and document corpus from a commercial medical search engine, we study the performance of 11 candidate query ranking approaches from the literature and analyze where they are effective. We show that the most effective approaches to query auto-completion are largely dependent on the number of characters that the user has typed so far, with the most effective approach differing for short and long prefixes. Moreover, we show that if personalized information is available about the searcher, this additional information can be used to more effectively rank query candidate completions, regardless of the prefix length.
{"title":"Comparing Approaches for Query Autocompletion","authors":"Giovanni Di Santo, R. McCreadie, C. Macdonald, I. Ounis","doi":"10.1145/2766462.2767829","DOIUrl":"https://doi.org/10.1145/2766462.2767829","url":null,"abstract":"Within a search engine, query auto-completion aims to predict the final query the user wants to enter as they type, with the aim of reducing query entry time and potentially preparing the search results in advance of query submission. There are a large number of approaches to automatically rank candidate queries for the purposes of auto-completion. However, no study exists that compares these approaches on a single dataset. Hence, in this paper, we present a comparison study between current approaches to rank candidate query completions for the user query as it is typed. Using a query-log and document corpus from a commercial medical search engine, we study the performance of 11 candidate query ranking approaches from the literature and analyze where they are effective. We show that the most effective approaches to query auto-completion are largely dependent on the number of characters that the user has typed so far, with the most effective approach differing for short and long prefixes. Moreover, we show that if personalized information is available about the searcher, this additional information can be used to more effectively rank query candidate completions, regardless of the prefix length.","PeriodicalId":297035,"journal":{"name":"Proceedings of the 38th International ACM SIGIR Conference on Research and Development in Information Retrieval","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122511803","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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