7 results on '"Gamage, Chandana"'
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2. Structure Effect on Pseudocapacitive Properties of A2LaMn2O7(A = Ca, Sr)
- Author
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Kananke-Gamage, Chandana C. W. and Ramezanipour, Farshid
- Abstract
Herein, the effect of structure on pseudocapacitive properties in alkaline conditions is demonstrated through the investigation of isoelectronic oxides Ca2LaMn2O7and Sr2LaMn2O7, where the difference in ionic radii of Ca2+and Sr2+leads to a change in structure and lattice symmetry, resulting in an orthorhombic Cmcmstructure for the former and a tetragonal I4/mmmstructure for the latter. While calcium and strontium do not make a direct contribution to the near‐surface faradaic processes that are essential to the pseudocapacitive properties, their effect on the structure leads to a change in the oxygen intercalation process and the associated pseudocapacitive energy storage. It is shown that Sr2LaMn2O7has a significantly greater specific capacitance than Ca2LaMn2O7. In addition, the former shows a considerably higher‐energy density compared to the latter. Furthermore, these materials show highly stable energy‐storage properties, and retain their specific capacitance over 10 000 cycles of charge–discharge in a symmetric pseudocapacitive cell. Importantly, these findings show the structure–property relationships, where a change in the structure and lattice symmetry can result in a significant change in pseudocapacitive charge–discharge properties in isoelectronic systems. The effect of structural symmetry on pseudocapacitive properties is studied through investigation of the isoelectronic oxides Ca2LaMn2O7and Sr2LaMn2O7, where the change in lattice symmetry results in a significant enhancement of pseudocapacitive properties.
- Published
- 2023
- Full Text
- View/download PDF
3. One-Time Sensors: A Novel Concept to Mitigate Node-Capture Attacks.
- Author
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Molva, Refik, Tsudik, Gene, Westhoff, Dirk, Bicakci, Kemal, Gamage, Chandana, Crispo, Bruno, and Tanenbaum, Andrew S.
- Abstract
Dealing with captured nodes is generally accepted as the most difficult challenge to wireless sensor network security. By utilizing the low-cost property of sensor nodes, we introduce the novel concept of one-time sensors to mitigate node-capture attacks. The basic idea is to load each sensor with only one cryptographic token so that the captured node can inject only a single malicious message into the network. In addition, sybil attacks are avoided and explicit revocation is not necessary using one-time sensors. By using public key techniques, one-way hash functions and Merkle's hash tree, we also show efficient implementations and interesting tradeoffs for one-time sensors. Keywords: Sensor network security, one-time sensor, node-capture attack, sybil attack, Merkle's hash tree. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
4. High Performance Agile Crypto Modules.
- Author
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Dawson, Ed, Clark, Andrew, Boyd, Colin, Gamage, Chandana G., Leiwo, Jussipekka, and Yuliang Zheng
- Abstract
This paper examines the impact of the primary symmetric key cryptographic operation on network data streams, encryption of user data, have on the overall traffic throughput. The encryption function which provides the basic confidentiality security service is studied from two cryptographic design perspectives based on the ability of a network cipher unit to dynamically re-parameterize itself while processing a high speed data stream. The designs studied in this paper were chosen based on their suitability for high speed network operation and their flexibility in satisfying dynamic security requirements. We develop analytical techniques to model the performance of each scheme. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
5. A Security Design for a Wide-Area Distributed System.
- Author
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JooSeok Song, Leiwo, Jussipekka, Hänle, Christoph, Homburg, Philip, Gamage, Chandana, and Tanenbaum, Andrew S.
- Abstract
Designing security of wide-area distributed systems is a highly complicated task. The complexity of underlying distribution and replication infrastructures together with the diversity of application scenarios increases the number of security requirements that must be addressed. High assurance requires the security enforcement to be isolated from non-security relevant functions and limited in the size of implementation. The major challenge in the is to find a balance between the diversity of security requirements and the need for high assurance. This paper addresses this conflict using Globe system as a reference framework, and establishes a security design that provides a flexible means of addressing the variety of security requirements of different application domains. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
6. Why Hierarchical Key Distribution Is Appropriate for Multicast Networks.
- Author
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JooSeok Song, Gamage, Chandana, Leiwo, Jussipekka, and Yuliang Zheng
- Abstract
The design rationale for many key distribution schemes for multicast networks are based on heuristic arguments on efficiency, flexibility and scalability. In most instances the choice of key server placement in a multicast network architecture is based on intuitive cryptographic considerations. We use an analytical model of multicast group formation and network growth to look at the selection of a key distribution scheme from a network operation perspective. Thereafter, this model is used to validate the choice of hierarchical (hybrid) key distribution model as the most appropriate. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
7. Employee perception towards electronic monitoring at work place and its impact on job satisfaction of software professionals in Sri Lanka.
- Author
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Samaranayake, Viraj and Gamage, Chandana
- Subjects
ELECTRONIC monitoring in the workplace ,JOB satisfaction ,COMMUNICATION in personnel management ,PROFESSIONAL employees ,EMPLOYEE misconduct ,STATISTICAL sampling ,QUALITY of work life ,EMAIL - Abstract
Abstract: Electronic monitoring is a rapidly growing phenomenon in Sri Lankan software industry. It allows employers to observe what employees do on the job and review employee communications, including e-mail and internet activity that employees consider private. Often, employers use electronic monitoring to ensure organizational confidentiality, limiting employer liability for employee misconduct. From the perspective of employees, electronic monitoring by employers involves several privacy and confidentiality concerns. Most of the time, employee performance and productivity aspects captured via electronic monitoring are effectively used by the Human Resources Departments, for decision making associated with the employees. Majority of the software development organizations in Sri Lanka today use some means of electronic technology to monitor their employee activities. Most of the time, employee perception towards electronic monitoring at work, contradicts with the need for law enforcement within the organization intended by the top management. Employers justify electronic monitoring at work place in terms of protecting the company’s confidential information, preventing the misuse of the organizational resources while uplifting the quality of work and productivity. On the other hand, the mutual trust that should be there between the employer and the employee is in question. Therefore, this study empirically investigated the relationship that might exist between the software professionals’ perception towards electronic monitoring at work place and its impact on their job satisfaction. Based on disproportionate stratified random sampling, data were collected from 380 software professionals in Sri Lanka, by administrating a structured questionnaire in which items were of 5 point Lickert scale. The data analysis included the univariate, bivariate and multivariate analyses. In this study, Perceived Relevance to Work and Personal Judgment of Effectiveness which were two variables used to measure perception of electronic monitoring were positively correlated with Job Satisfaction. This means that the software professionals, who view electronic monitoring as something which is relevant to their work as well as which uplifts the quality of their work, are satisfied in their jobs. Perceived Invasion of Privacy was negatively correlated to Job Satisfaction, which sheds some light in organizational electronic monitoring policy making. Also, Perceived Task Satisfaction was negatively correlated to Job Satisfaction. This means that the software professionals, who thought that working in an electronically monitored environment makes their tasks more complex, are rather dissatisfied in the job. Also, it appeared that the impact of electronic monitoring at work place on the job satisfaction of software professionals becomes less significant along with higher professional experience. The findings of this research can be incorporated in IT security policy making in the software development organizations in Sri Lanka and in similar economics, with a special emphasis on the job satisfaction of their employees, which is the most valuable asset of the organization. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
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