Stephen Kimani - Academia.edu (original) (raw)

Papers by Stephen Kimani

International Journal of Computer Applications, 2015

In this study, we reviewed biometric template protection schemes in subsisting literature and est... more In this study, we reviewed biometric template protection schemes in subsisting literature and established that there is no reliable, efficacious and foolproof technique that assures diversity, revocability, security and optimal performance as is required of an ideal biometric template security scheme. This status of affairs motivated us to contrivance an approach that derives biometric encryption keys from biometric fingerprint templates. The technique we proposed involves a two-step enrollment and authentication of fingerprints while encrypting fingerprint templates with encryption keys derived from other biometric fingerprint templates before archiving them to a database. The system was implemented using Java, developed on Netbeans 8.0 IDE, MySQL RDBMS was used for back-end database and utilized Source AFIS java library framework for fingerprint verification and identification. Test results were carried out to determine the system's efficacy.

International journal of medical informatics, 2011

Journal of Visual Languages & Computing, 2014

Objective: In this paper we present a Visual Query System, which allows users to graphically buil... more Objective: In this paper we present a Visual Query System, which allows users to graphically build queries over data streams and traditional relational data. The Visual Query System runs on top of a DSMS (Data Stream Management System). Methods: The system has been designed and implemented following the user-centered design approach. Two different releases of the system have been incrementally and iteratively designed and evaluated. The first release has been evaluated using heuristic evaluation. The second release, whose design was a refinement based on the results of the foregoing heuristic evaluation, was evaluated by several users. Moreover, a comparative evaluation involving users has been conducted on the second release. Results: The paper presents the visual query system, and the results ofthe various evaluations. Conclusion: Visual Query Systems for data streams are an effective tool for industrial engineers in querying and analyzing data streams from equipments. Practice and implications: The proposed visual query system has been employed in real industrial scenarios in order to visually query and analyze data streams produced by industrial machines.

Lecture Notes in Computer Science, 2011

The success of online social networking systems has revolutionised online sharing and communicati... more The success of online social networking systems has revolutionised online sharing and communication, however it has also contributed significantly to the infamous information overload problem. Social Networking systems aggregate network activities into chronologically ordered lists, Network Feeds, as a way of summarising network activity for its users. Unfortunately, these feeds do not take into account the interests of the user viewing them or the relevance of each feed item to the viewer. Consequently individuals often miss out on important updates. This work aims to reduce the burden on users of identifying relevant feed items by exploiting observed user interactions with content and people on the network and facilitates the personalization of network feeds in a manner which promotes relevant activities. We present the results of a large scale live evaluation which shows that personalized feeds are more successful at attracting user attention than non-personalized feeds.

Lecture Notes in Computer Science, 2004

Most of the existing efforts for supporting the preparation and delivery of accessible e-learning... more Most of the existing efforts for supporting the preparation and delivery of accessible e-learning materials propose guidelines that prevalently ad-dress technical accessibility issues. However, little or no consideration is given to the didactical creators in the learning material preparation. The existing guidelines also usually provide generic indications on alternative forms of didactical content to enable equivalent access of the content. However, the sole provision of equivalent forms does not guarantee effective access. While this ...

Human Factors and Ergonomics, 2009

in pres

Synthesis Lectures on Data Management, 2010

This lecture covers several core issues in user-centered data management, including how to design... more This lecture covers several core issues in user-centered data management, including how to design usable interfaces that suitably support database tasks, and relevant approaches to visual querying, information visualization, and visual data mining. Novel interaction paradigms, e.g., mobile and interfaces that go beyond the visual dimension, are also discussed.

Lecture Notes in Computer Science, 2005

In an age characterized by tremendous technological breakthroughs, the world is witnessing overwh... more In an age characterized by tremendous technological breakthroughs, the world is witnessing overwhelming quantities and types of information. Digital Libraries (DLs) are a result of these breakthroughs, but they have not been spared by the challenges resulting from them. While DLs stakeholders are still struggling to come to terms with the massive quantities and complex types of information, the needs of the digital library as an information/knowledge environment is still evolving including new challenging needs. Information Visualization (Infovis) represents a viable solution to this. The human-vision channel has a high bandwidth and it can surveil a visual field in a parallel manner, processing the corresponding data to different levels of detail and recognition and understanding of overwhelming data can be done at an instant. It is an outstanding resource that can be exploited within a DLs in order to address issues arising from the conventional needs (such as the quantities and types of information) and the non-conventional needs. Here we analyze Infovis as a resource for DLs, relating visualization techniques to specific DLs needs, providing a classification of Infovis techniques and reporting about our analysis of DLs tasks and their correspondence with suitable visualizations.

International Journal of Computer Applications, 2014

In today's world, increasing number of networks connected to the Internet poses a great challenge... more In today's world, increasing number of networks connected to the Internet poses a great challenge on security issues. Many defensive mechanisms exist and one such higher level mechanism is network intrusion detection system. Intrusion detection system is a process of intelligently monitoring the events in an individual system or network, analysing them for signs of violation of security policy. Two major classifications of intrusion detection systems are misuse and anomaly intrusion detection systems. Misuse detection system refers to detection of intrusions that follow well defined intrusion patterns. Anomaly detection model refers to detection performed by detecting changes in the behaviour of the system. Many data mining techniques like k-Nearest Neighbour (kNN), Association Rule Mining etc., have been applied to intrusion detection. This paper aims at application of kNN to a subset of records from the KDD Cup 1999 dataset for classification of connection records into normal or attacked data. The paper also applies kNN to the subset of records with the selected features proposed by Kok-Chin-Khor et al to compare the classifications.

Encyclopedia of Database Systems, 2009

Creation of web wrappers (i.e programs that extract data from the web) is a subject of study in t... more Creation of web wrappers (i.e programs that extract data from the web) is a subject of study in the field of web data extraction. Designing a domainspecific language for a web wrapper is a challenging task, because it introduces trade-offs between expressiveness of a wrapper's language and safety. In addition, little attention has been paid to execution of a wrapper in restricted environment. In this thesis, we present a new wrapping language -Serrano -that has three goals in mind. (1) Ability to run in restricted environment, such as a browser extension, (2) extensibility, to balance the tradeoffs between expressiveness of a command set and safety, and (3) processing capabilities, to eliminate the need for additional programs to clean the extracted data. Serrano has been successfully deployed in a number of projects and provided encouraging results.

Lecture Notes in Computer Science, 2013

ABSTRACT Nowadays, industrial engineering environments are typically characterized by sensors whi... more ABSTRACT Nowadays, industrial engineering environments are typically characterized by sensors which stream massive amounts of different types of data. It is often difficult for industrial engineers to query, interact with, and interpret the data. In order to process many different kinds of distributed data stream sources originating from different kinds of data sources, a distributed federated data stream management system (FDSMS) is necessary. Although there exist some research efforts aimed at providing visual interfaces for querying temporal and real time data, there is virtually no existing work that provides a visual query specification and interaction interface that directly corresponds to a distributed federated data stream management system. This paper describes a visual environment that supports users in visually specifying queries and interacting with industrial engineering data. The visual environment comprises: a visual query specification and interaction environment, and a corresponding visual query language that runs on top of a distributed FDSMS.

Proceedings of the Working Conference on Advanced Visual Interfaces, 2002

Abstract. It cannot be overstated that the knowledge discovery process still presents formidable ... more Abstract. It cannot be overstated that the knowledge discovery process still presents formidable challenges. One of the main issues in knowledge discovery is the need for an overall framework that can support the entire discovery process. It is worth noting the role and place of visualization in such a framework. Visualization enables or triggers the user to use his/her outstanding visual and mental capabilities, thereby gaining insight and understanding of data. The foregoing points to the pivotal role that visualization can play ...

Concepts, Methodologies, Tools, and Applications

The traditional desktop computing paradigm has had major successes. It also should be noted that ... more The traditional desktop computing paradigm has had major successes. It also should be noted that we are in a day and age where many good computer and device users are increasingly finding themselves being required to perform their activities not in offices/desktops but in real-world settings. Ubiquitous computing can make possible in the real-world setting what would have otherwise been impossible through desktop computing. However, there is a world of difference between the real-world and the desktop settings. The move from the desktop to the real-world settings raises various issues when we consider the nature of tasks that the ubiquitous devices/applications would be expected to support and the real-world context in which they will be used. A careful study of the nature of tasks in ubiquitous computing can make some design requirements in the development of ubiquitous applications more evident. This chapter proposes ubiquitous application design and evaluation considerations emerging from a deeper understanding of the nature of tasks in ubiquitous computing.

2010 IEEE 23rd International Symposium on Computer-Based Medical Systems (CBMS), 2010

Sustaining user participation is a challenge for even the most popular web sites. In this work we... more Sustaining user participation is a challenge for even the most popular web sites. In this work we report on an effort to increase exposure to, and interaction with, a repository of health based information by coupling the repository with a social networking application. We hypothesize that we can sustain user interaction with a repository and increase nutrition knowledge through content browsing by reporting on the browsing actions of other users in a Social Networking System's activity feeds. We report on the findings of a live user study, which showed that coupling health content with a social networking system successfully increased content browsing and that highly engaged users are seen to have an altered attitude toward control over their health.

Encyclopedia of Database Systems, 2009

Encyclopedia of Database Systems, 2009

Encyclopedia of Database Systems, 2009

Advances in Integrated Soil Fertility Management in sub-Saharan Africa: Challenges and Opportunities

... Urban Agriculture as an Asset Strategy, Supplementing Income and diets. Etuah-Jackson, Klaass... more ... Urban Agriculture as an Asset Strategy, Supplementing Income and diets. Etuah-Jackson, Klaassen WP and Awuye JA 2001. Turning Munic-ipal Waste into Compost: The Case of Accra. ... Ottawa, Canada. p. 146. Lekasi JK, Tanner JC, Kimani SK and Harris PJC 2002. ...

Encyclopedia of Database Systems, 2009

The World Wide Web became one of the most valuable resources for information retrievals and knowl... more The World Wide Web became one of the most valuable resources for information retrievals and knowledge discoveries due to the permanent increasing of the amount of data available online. Taking into consideration the web dimension, the users get easily lost in the web's rich hyper structure. Application of data mining methods is the right solution for knowledge discovery on the Web. The knowledge extracted from the Web can be used to raise the performances for Web information retrievals, question answering and Web based data warehousing. In this paper, I provide an introduction of Web mining categories and I focus on one of these categories: the Web structure mining. Web structure mining, one of three categories of web mining for data, is a tool used to identify the relationship between Web pages linked by information or direct link connection. It offers information about how different pages are linked together to form this huge web. Web Structure Mining finds hidden basic structures and uses hyperlinks for more web applications such as web search.

Proceedings of the 4th International Conference on Persuasive Technology, 2009

Engagement with computer games causes children and adolescent users to spend a substantial amount... more Engagement with computer games causes children and adolescent users to spend a substantial amount of time at sedentary game playing activity. We hypothesise that this engagement can be leveraged to motivate users to increase their amount of physical activity. In this paper, we present a novel approach for designing computer games, according to which the users' physical activity reinforces their game character. This way the users are seamlessly motivated to perform physical activity while maintaining their enjoyment of playing the game.

International Journal of Computer Applications, 2015

In this study, we reviewed biometric template protection schemes in subsisting literature and est... more In this study, we reviewed biometric template protection schemes in subsisting literature and established that there is no reliable, efficacious and foolproof technique that assures diversity, revocability, security and optimal performance as is required of an ideal biometric template security scheme. This status of affairs motivated us to contrivance an approach that derives biometric encryption keys from biometric fingerprint templates. The technique we proposed involves a two-step enrollment and authentication of fingerprints while encrypting fingerprint templates with encryption keys derived from other biometric fingerprint templates before archiving them to a database. The system was implemented using Java, developed on Netbeans 8.0 IDE, MySQL RDBMS was used for back-end database and utilized Source AFIS java library framework for fingerprint verification and identification. Test results were carried out to determine the system's efficacy.

International journal of medical informatics, 2011

Journal of Visual Languages & Computing, 2014

Objective: In this paper we present a Visual Query System, which allows users to graphically buil... more Objective: In this paper we present a Visual Query System, which allows users to graphically build queries over data streams and traditional relational data. The Visual Query System runs on top of a DSMS (Data Stream Management System). Methods: The system has been designed and implemented following the user-centered design approach. Two different releases of the system have been incrementally and iteratively designed and evaluated. The first release has been evaluated using heuristic evaluation. The second release, whose design was a refinement based on the results of the foregoing heuristic evaluation, was evaluated by several users. Moreover, a comparative evaluation involving users has been conducted on the second release. Results: The paper presents the visual query system, and the results ofthe various evaluations. Conclusion: Visual Query Systems for data streams are an effective tool for industrial engineers in querying and analyzing data streams from equipments. Practice and implications: The proposed visual query system has been employed in real industrial scenarios in order to visually query and analyze data streams produced by industrial machines.

Lecture Notes in Computer Science, 2011

The success of online social networking systems has revolutionised online sharing and communicati... more The success of online social networking systems has revolutionised online sharing and communication, however it has also contributed significantly to the infamous information overload problem. Social Networking systems aggregate network activities into chronologically ordered lists, Network Feeds, as a way of summarising network activity for its users. Unfortunately, these feeds do not take into account the interests of the user viewing them or the relevance of each feed item to the viewer. Consequently individuals often miss out on important updates. This work aims to reduce the burden on users of identifying relevant feed items by exploiting observed user interactions with content and people on the network and facilitates the personalization of network feeds in a manner which promotes relevant activities. We present the results of a large scale live evaluation which shows that personalized feeds are more successful at attracting user attention than non-personalized feeds.

Lecture Notes in Computer Science, 2004

Most of the existing efforts for supporting the preparation and delivery of accessible e-learning... more Most of the existing efforts for supporting the preparation and delivery of accessible e-learning materials propose guidelines that prevalently ad-dress technical accessibility issues. However, little or no consideration is given to the didactical creators in the learning material preparation. The existing guidelines also usually provide generic indications on alternative forms of didactical content to enable equivalent access of the content. However, the sole provision of equivalent forms does not guarantee effective access. While this ...

Human Factors and Ergonomics, 2009

in pres

Synthesis Lectures on Data Management, 2010

This lecture covers several core issues in user-centered data management, including how to design... more This lecture covers several core issues in user-centered data management, including how to design usable interfaces that suitably support database tasks, and relevant approaches to visual querying, information visualization, and visual data mining. Novel interaction paradigms, e.g., mobile and interfaces that go beyond the visual dimension, are also discussed.

Lecture Notes in Computer Science, 2005

In an age characterized by tremendous technological breakthroughs, the world is witnessing overwh... more In an age characterized by tremendous technological breakthroughs, the world is witnessing overwhelming quantities and types of information. Digital Libraries (DLs) are a result of these breakthroughs, but they have not been spared by the challenges resulting from them. While DLs stakeholders are still struggling to come to terms with the massive quantities and complex types of information, the needs of the digital library as an information/knowledge environment is still evolving including new challenging needs. Information Visualization (Infovis) represents a viable solution to this. The human-vision channel has a high bandwidth and it can surveil a visual field in a parallel manner, processing the corresponding data to different levels of detail and recognition and understanding of overwhelming data can be done at an instant. It is an outstanding resource that can be exploited within a DLs in order to address issues arising from the conventional needs (such as the quantities and types of information) and the non-conventional needs. Here we analyze Infovis as a resource for DLs, relating visualization techniques to specific DLs needs, providing a classification of Infovis techniques and reporting about our analysis of DLs tasks and their correspondence with suitable visualizations.

International Journal of Computer Applications, 2014

In today's world, increasing number of networks connected to the Internet poses a great challenge... more In today's world, increasing number of networks connected to the Internet poses a great challenge on security issues. Many defensive mechanisms exist and one such higher level mechanism is network intrusion detection system. Intrusion detection system is a process of intelligently monitoring the events in an individual system or network, analysing them for signs of violation of security policy. Two major classifications of intrusion detection systems are misuse and anomaly intrusion detection systems. Misuse detection system refers to detection of intrusions that follow well defined intrusion patterns. Anomaly detection model refers to detection performed by detecting changes in the behaviour of the system. Many data mining techniques like k-Nearest Neighbour (kNN), Association Rule Mining etc., have been applied to intrusion detection. This paper aims at application of kNN to a subset of records from the KDD Cup 1999 dataset for classification of connection records into normal or attacked data. The paper also applies kNN to the subset of records with the selected features proposed by Kok-Chin-Khor et al to compare the classifications.

Encyclopedia of Database Systems, 2009

Creation of web wrappers (i.e programs that extract data from the web) is a subject of study in t... more Creation of web wrappers (i.e programs that extract data from the web) is a subject of study in the field of web data extraction. Designing a domainspecific language for a web wrapper is a challenging task, because it introduces trade-offs between expressiveness of a wrapper's language and safety. In addition, little attention has been paid to execution of a wrapper in restricted environment. In this thesis, we present a new wrapping language -Serrano -that has three goals in mind. (1) Ability to run in restricted environment, such as a browser extension, (2) extensibility, to balance the tradeoffs between expressiveness of a command set and safety, and (3) processing capabilities, to eliminate the need for additional programs to clean the extracted data. Serrano has been successfully deployed in a number of projects and provided encouraging results.

Lecture Notes in Computer Science, 2013

ABSTRACT Nowadays, industrial engineering environments are typically characterized by sensors whi... more ABSTRACT Nowadays, industrial engineering environments are typically characterized by sensors which stream massive amounts of different types of data. It is often difficult for industrial engineers to query, interact with, and interpret the data. In order to process many different kinds of distributed data stream sources originating from different kinds of data sources, a distributed federated data stream management system (FDSMS) is necessary. Although there exist some research efforts aimed at providing visual interfaces for querying temporal and real time data, there is virtually no existing work that provides a visual query specification and interaction interface that directly corresponds to a distributed federated data stream management system. This paper describes a visual environment that supports users in visually specifying queries and interacting with industrial engineering data. The visual environment comprises: a visual query specification and interaction environment, and a corresponding visual query language that runs on top of a distributed FDSMS.

Proceedings of the Working Conference on Advanced Visual Interfaces, 2002

Abstract. It cannot be overstated that the knowledge discovery process still presents formidable ... more Abstract. It cannot be overstated that the knowledge discovery process still presents formidable challenges. One of the main issues in knowledge discovery is the need for an overall framework that can support the entire discovery process. It is worth noting the role and place of visualization in such a framework. Visualization enables or triggers the user to use his/her outstanding visual and mental capabilities, thereby gaining insight and understanding of data. The foregoing points to the pivotal role that visualization can play ...

Concepts, Methodologies, Tools, and Applications

The traditional desktop computing paradigm has had major successes. It also should be noted that ... more The traditional desktop computing paradigm has had major successes. It also should be noted that we are in a day and age where many good computer and device users are increasingly finding themselves being required to perform their activities not in offices/desktops but in real-world settings. Ubiquitous computing can make possible in the real-world setting what would have otherwise been impossible through desktop computing. However, there is a world of difference between the real-world and the desktop settings. The move from the desktop to the real-world settings raises various issues when we consider the nature of tasks that the ubiquitous devices/applications would be expected to support and the real-world context in which they will be used. A careful study of the nature of tasks in ubiquitous computing can make some design requirements in the development of ubiquitous applications more evident. This chapter proposes ubiquitous application design and evaluation considerations emerging from a deeper understanding of the nature of tasks in ubiquitous computing.

2010 IEEE 23rd International Symposium on Computer-Based Medical Systems (CBMS), 2010

Sustaining user participation is a challenge for even the most popular web sites. In this work we... more Sustaining user participation is a challenge for even the most popular web sites. In this work we report on an effort to increase exposure to, and interaction with, a repository of health based information by coupling the repository with a social networking application. We hypothesize that we can sustain user interaction with a repository and increase nutrition knowledge through content browsing by reporting on the browsing actions of other users in a Social Networking System's activity feeds. We report on the findings of a live user study, which showed that coupling health content with a social networking system successfully increased content browsing and that highly engaged users are seen to have an altered attitude toward control over their health.

Encyclopedia of Database Systems, 2009

Encyclopedia of Database Systems, 2009

Encyclopedia of Database Systems, 2009

Advances in Integrated Soil Fertility Management in sub-Saharan Africa: Challenges and Opportunities

... Urban Agriculture as an Asset Strategy, Supplementing Income and diets. Etuah-Jackson, Klaass... more ... Urban Agriculture as an Asset Strategy, Supplementing Income and diets. Etuah-Jackson, Klaassen WP and Awuye JA 2001. Turning Munic-ipal Waste into Compost: The Case of Accra. ... Ottawa, Canada. p. 146. Lekasi JK, Tanner JC, Kimani SK and Harris PJC 2002. ...

Encyclopedia of Database Systems, 2009

The World Wide Web became one of the most valuable resources for information retrievals and knowl... more The World Wide Web became one of the most valuable resources for information retrievals and knowledge discoveries due to the permanent increasing of the amount of data available online. Taking into consideration the web dimension, the users get easily lost in the web's rich hyper structure. Application of data mining methods is the right solution for knowledge discovery on the Web. The knowledge extracted from the Web can be used to raise the performances for Web information retrievals, question answering and Web based data warehousing. In this paper, I provide an introduction of Web mining categories and I focus on one of these categories: the Web structure mining. Web structure mining, one of three categories of web mining for data, is a tool used to identify the relationship between Web pages linked by information or direct link connection. It offers information about how different pages are linked together to form this huge web. Web Structure Mining finds hidden basic structures and uses hyperlinks for more web applications such as web search.

Proceedings of the 4th International Conference on Persuasive Technology, 2009

Engagement with computer games causes children and adolescent users to spend a substantial amount... more Engagement with computer games causes children and adolescent users to spend a substantial amount of time at sedentary game playing activity. We hypothesise that this engagement can be leveraged to motivate users to increase their amount of physical activity. In this paper, we present a novel approach for designing computer games, according to which the users' physical activity reinforces their game character. This way the users are seamlessly motivated to perform physical activity while maintaining their enjoyment of playing the game.