• Journal of Communications and Networks
• /
• v.14 no.4
• /
• pp.418-428
• /
• 2012

With the requirement for providing multiple levels of access control for group members, many group key management schemes designed for hierarchical access control have been put forward. However, most of these schemes focus on the efficiency of group key establishment and rekeying in centralized environments. This paper proposes an integrated group key agreement (IGK) scheme for contributory environments. The IGK scheme employs the integrated key graph to remove key redundancies existing in single key trees, and reduces key establishment and rekeying time while providing hierarchical access control. Performance analyses and simulations conducted with respect to computation and communication overheads indicate that our proposed IGK scheme is more efficient than the independent group key agreement scheme.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1938-1943
• /
• 2005

Network human-robot interface is an important research topic. In home application, users access the robotic system directly via voice, gestures or through the network. Users explore a system by using the services provided by this system and to some extend users are enable to participate in a service as partners. A service may be provided by a robot, a group of robots or robots and other network connected systems (distributed sensors, information systems, etc). All these services are done in the network environment, where uncertainty such as the unstable network connection, the availability of the partners in a service, exists. Moreover, these services are controlled by several users, accessing at different time by different methods. Our research aimed at solving this problem to provide a high available level, flexible coordination system. In this paper, a multi-agent framework is proposed. This framework is validated by using our new concept of slave agents, a responsive multi-agent environment, a virtual directory facilitator (VDF), and a task allocation system using contract net protocol. Our system uses a mixed model between distributed and centralized model. It uses a centralized agent management system (AMS) to control the overall system. However, the partners and users may be distributed agents connected to the center through agent communication or centralized at the AMS container using the slave agents to represent the physical agents. The system is able to determine the task allocation for a group of robot working as a team to provide a service. A number of experiments have been conducted successfully in our lab environment using Issac robot, a PDA for user agent and a wireless network system, operated under our multi agent framework control. The experiments show that this framework works well and provides some advantages to existing systems.

• Nuclear Engineering and Technology
• /
• v.56 no.3
• /
• pp.855-865
• /
• 2024

Commercial deployment of nuclear microreactors presents an opportunity for the industry to rethink its approach to manufacturing, siting, operation and maintenance, and fuel cycle management as certain principles used in grid-scale nuclear projects are not applicable to a decentralized microreactor economy. The success of this nascent industry is dependent on its ability to reduce infrastructure, logistical, regulatory and lifecycle costs. A utility-like 'Central Facility' that consolidates the services required and responsibilities borne by vendors into one or a few centralized locations will be necessary to support the deployment of a fleet of microreactors. This paper discusses the requirements for a Central Facility, its implications on the cost structures of owners and suppliers of microreactors, and the impact of the facility for the broader microreactor industry. In addition, this paper discusses the pre-requisites for eligibility as well as the opportunities for a Central Facility host site. While there are many suitable locations for such a capability across the U.S., this paper considers a facility co-located with the Vogtle Nuclear Power Plant and Savannah River Sites to illustrate how a Central Facility can leverage the existing infrastructure and stimulate a local ecosystem.

• Convergence Security Journal
• /
• v.8 no.1
• /
• pp.143-152
• /
• 2008

Sensor networks have a wide spectrum of military and civil applications, particularly with respect to security and secure keys for encryption and authentication. This thesis presents a new centralized approach which focuses on the group key distribution with revocation capability for Wireless Sensor Networks. We propose a new personal key share distribution. When utilized, this approach proves to be secure against k-number of illegitimate colluding nodes. In contrast to related approaches, our scheme can overcome the security shortcomings while keeping the small overhead requirements per node. It will be shown that our scheme is unconditionally secure and achieves both forward secrecy and backward secrecy. The analysis is demonstrated in terms of communication and storage overheads.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.49 no.9
• /
• pp.18-26
• /
• 2012

As the performance of the next-generation broadband wireless networks is dramatically enhanced, various services (i.e., education, video conferencing, online games, etc.) have been provided to users through a smart mobile platform. Since those services are usually provided by using the centralized architecture, it is difficult for a lot of users to provide the scalable communication service with regard to traffic management. To solve these problems, we have proposed an architecture of P2P-based group communication management scheme using smart mobile device. More specifically, we design the group management protocol and algorithm for the group member management and the traffic management. By using these methods, the mobile multimedia streaming service can be provided with scalability. In order to verify the performance of the proposed scheme, we have mathematically analyzed the performance in terms of the average transmission delay and bandwidth utilization.

• Asia-Pacific Journal of Business
• /
• v.3 no.2
• /
• pp.23-33
• /
• 2012

Sustainable competitive advantage depends on formulation and implementation of appropriate human resource management (HRM) strategies and deployment of their competencies effectively in dynamic and complex environment. Competencies deployment is an approach to make decisions on the intentions and plans of organization concerning employment relationship and its recruitment, training, development, performance appraisal, reward and employee relations policies and practice. The improvement of organizational effectiveness is an overall objective of people management in organizations. In light of these, this study explores the present practices of HRM like: HR departments, HR policies and strategies, HR planning, recruitment selection and placement, training and development, performance appraisal, compensation and benefit, employee relations and communications. Based on the survey in 204 Nepalese organizations as a unit of analysis, the study concludes that HR practices in few organizations have action program for minorities, ethnic group, older employees and people with disabilities. Due to centralized organizational structure, most of HR decisions are taken into central office and line managers being involved highly in planning and implementing HR policies. In a nutshell, though HRM practices are not developed like developed countries, Nepalese organizations are realizing the significance of people management at work and changing their practices in the present dynamic environment.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.49 no.12
• /
• pp.81-88
• /
• 2012

As the performance of the next-generation broadband wireless networks is dramatically enhanced, various services (i.e., education, Live video streaming, Live video conferencing, online games, etc.) have been provided to users through a smart mobile platform. Those services are usually provided by using the centralized communication server. However, since all multimedia traffic is exchanged through a communication server, it often has the scalability problem with regard to traffic management. Our main purpose is for group smart users to provide scalable live multimedia streaming service based on P2P network. To do this, we have designed an architecture of P2P-based service management for mobile group communication management and service management protocol. In order to verify the performance of the proposed scheme, we have mathematically analyzed the performance in terms of the average transmission delay and bandwid th utilization.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 2003.07a
• /
• pp.293-295
• /
• 2003

본 논문에서는 멀티캐스트기법에 기반한 중앙분배방식의 그룹키 관리 기법에 대한 안전성 모델을 제시하고자 한다. 지금까지 키 관리 기법과 관련한 안전성 모델 연구는 주로 두 사용자간에 안전한 키 교환이 이루어지는 환경에 집중되어 왔다. 이와 달리 본 논문에서 다루는 환경은 특정 그룹에 속한 다수의 사용자가 안전하게 키를 공유하는 것을 목적으로 하며 이때 키 생성, 키 분배 등의 그룹키 관리를 위해 신뢰기관인 그룹 관리자가 존재한다. 이러한 중앙분배방식의 그룹키 관리가 안전하게 이루어지기 위해 반드시 요구되어지는 안전성 조건을 분석하고 이를 기반으로 구체적인 안전성 모델을 제시한다.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.13 no.3
• /
• pp.101-110
• /
• 2003

Secure and reliable group communication is an increasingly active research area prompted by the growing popularity of many types of group-oriented and collaborative applications. The central challenge is secure and efficient group key management. While centralized methods are often appropriate for key distribution in large multicast-style groups, many collaborative group settings require distributed key agreement techniques. Most of prior group key agreement protocols have been focused on reducing the computational costs. One exception is STR protocol that optimizes communicational cost. On the other hand, it requires O(n) number of modular exponentiations. In this paper, we propose a new group key agreement protocol that modifies STR protocol by utilizing pairing based cryptography. The resulting protocol reduces computational cost of STR protocol while preserving the communication cost.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.8B
• /
• pp.757-763
• /
• 2006

In this paper, a novel multiple access scheme using SMA(Split and Merge Algorithm) is proposed to reduce the accessdelay of wireless MAC protocols. The key idea of the SMA is to dynamically split and merge the contending terminals depending on their traffic loads for effective control of access to the channels. The SMA divides the collided terminals into several sub-groups if a collision occurs and merges the idle terminals of the split sub-groups into their original group. The merge algorithm can be used to resolve collision and split operation can be used to dynamic group management. The simulation results indicate that our algorithm may provide a higher throughput and a lower collision rate than the existing algorithms, especially under heavy traffic loads.