• KIPS Transactions on Computer and Communication Systems
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• v.8 no.10
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• pp.245-250
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• 2019

The use of NAND flash memory has increased rapidly due to the development of mobile fields. However, NAND flash memory has a limited lifespan, so studies are underway to predict its lifespan. Workload is one of the factors that significantly affect the life of NAND flash memory, and workload analysis studies in mobile environments are insufficient. In this paper, we analyze the distribution of workload in the mobile environment by collecting traces generated by using Android-based smartphones. The collected traces can be divided into three groups of hotness. Also they are distributed in the form of heavy tails. We fit this to the Pareto, Lognormal, and Weibull distributions, and Traces are closest to the Pareto distribution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.7
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• pp.993-1000
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• 2002

In this paper, we design the CORBA-based Mobile Agent Model (CMAM) which has the capability of the efficient work processing in distributed environment through sensing network traffic and searching the optimal path for migration nodes of mobile agent. In case existing mobile agent model is given various works from user, the network overhead and traffic are increased by increasing of execution module size. Also, if it happens a large quantity of traffics due to migration of nodes according to appointment of the passive host(below node) routing schedule by user, it needs much cost for node search time by traffic. Therefore, in this paper, we design a new mobile agent m()del that assures the reliability of agent's migration through dynamic act on the specific situation according to appointment of the active routing schedule and can minimize agent's work processing time through optimal path search. The proposed model assigns routing schedule of the migration nodes actively using an extended MAFFinder. Also, for decreasing overhead of network by agent's size, it separates the existing mobile agent object by mobile agent including only agent calling module and push agent with work executing module based on distributed object type of CORBA. Also, it reduces the required time for round works of mobile agent through the optimal path search of migration nodes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.89-95
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• 2008

The introduction of wireless information technology gives rise to new mobile services in all kinds of areas of out daily life. Mobile healthcare system is a production of composite ICT (Information and Communication Technology) which focused on signal sensing, processing, and communication in wireless environment. The mobile and wireless revolution promises not only expanded access to patient health information, but also improved patient care. In this paper, we describe a surrogate host based mobile healthcare information system which utilized Grid computing for real-time ECG signal processing. The surrogate host provides seamless interface between mobile device and Medical Grid portal. The security extension of GSI (Grid Security Infrastructure) allows mobile users to access Grid portal in a secure and convenient manner. The presented system architecture can be used as a secure enterprise mobile healthcare system for hospital physicians.

• The Journal of Korean Association of Computer Education
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• v.11 no.5
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• pp.67-76
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• 2008

Grid computing has a large scale virtual computing environment that enables a collaborative processing through sharing resources of geographically distributed organizations. In recent year, the development of wireless networks and mobile devices enables mobile devices to consider as a resource of the grids. However, there are some problems such as low performance of processors, small capacity of storages, limited capacity of battery, and low bandwidth. In this paper, to overcome these limitations occurred in mobile grid environments, we proposed a proxy-based mobile grid system. Our proposed system enables mobile devices to play roles as a resource consumer and a resource provider and to collaborate with wired grids through a mobile router. Also, we propose an adaptive job scheduling scheme to cope with context changes of mobile devices and compare our scheduling scheme with other scheduling schemes using a simulation tool, SimGrid, to verify the validity of our job scheduling scheme.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.124-127
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• 1997

In this paper, we propose a method of cooperative control based on immune system in distributed autonomous robotic system(DARS). Immune system is living body's self-protection and self-maintenance system. Thus these features can be applied to decision making of optimal swarm behavior in dynamically changing environment. For the purpose of applying immune system to DARS, a robot is regarded as a B lymphocyte(B cell), each environmental condition as an antigen, and a behavior strategy as an antibody respectively. The executing process of proposed method is as follows. When the environmental condition changes, a robot selects an appropriate behavior strategy. And its behavior strategy is simulated and suppressed by other robot using communication. Finally much simulated strategy is adopted as a swarm behavior strategy. This control scheme is based on clonal selection and idiotopic network hypothesis. And it is used for decision making of optimal swarm strategy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1661-1678
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• 2016

Clustering is one of the key technologies in vehicular networks. Constructing and maintaining stable clusters is a challenging task in high mobility environments. DWCM (Distributed and Weighted Clustering based on Mobility Metrics) is proposed in this paper based on the d-hop dominating set of the network. Each vehicle is assigned a priority that describes the cluster relationship. The cluster structure is determined according to the d-hop dominating set, where the vehicles in the d-hop dominating set act as the cluster head nodes. In addition, cluster maintenance handles the cluster structure changes caused by node mobility. The rationality of the proposed algorithm is proven. Simulation results in the NS-2 and VanetMobiSim integrated environment demonstrate the performance advantages.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.129-135
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• 2019

Recently, studies have been conducted to improve the m-commerce process in the NFC-based mobile environment and the increase of the number of smart phones built in NFC. Since authentication is important in mobile electronic payment, FIDO(Fast IDentity Online) and 2 Factor electronic payment system are applied. In addition, block-chains using distributed raw materials have emerged as a representative technology of the fourth industry. In this study, for the mobile gallery auction of the traders using NFC embedded terminal (smartphone) in a small gallery auction in which an unspecified minority participates, password-based authentication and biometric authentication technology (fingerprint) were applied to record transaction details and ownership transfer of the auction participants in electronic payment. And, for the cost reduction and data integrity related to gallery auction, the private distributed director block chain was constructed and used. In addition, domestic and foreign cases applying block chain in the auction field were investigated and compared. In the future, the study will also study the implementation of block chain networks and smart contract and the integration of block chain and artificial intelligence to apply the proposed method.

• Proceedings of the Korea Information Assurance Society Conference
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• 2004.05a
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• pp.283-288
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• 2004

인터넷의 발전과 멀티미디어 인프라의 성장으로 방대한 양과, 다양한 종류의 디지털 데이터들이 제작, 유통되고 있다. 디지털 컨텐츠는 기존 아날로그 컨텐츠와 비교 생성, 가공, 유통, 분배등의 측면에서 많은 장점을 갖는 반면, 원본과 동일한 복사물을 쉽게 생성할 수 있는 특징 때문에 디지털 창작물에 대한 저작권 보호가 중요시된다. 본 논문은 이미 유선 환경에서 디지털 컨텐츠 보호 기술로 각광 받고 있는 DRM(Digital Rights Management)을 토대로 무선 환경에서 디지털 컨텐츠의 보안을 위한 Mobile DRM (MDRM) 에 대한 설계를 목적으로 한다 설계되어진 MDRM은 Mobile 환경을 고려 키 교환 및 컨텐츠 암/복호 시 발생하는 부하를 줄이고 컨텐츠의 불법적인 유포 방지를 위한 SDMS(Secret-Key Distributed Management System : 비밀키 분산 관리 시스템)기술을 이용한다.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.139-143
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• 2005

The P2P is a network environment supporting data exchange which is directly connected peers without limit of existing server-client and intervening central server for resource or offered service with each peer. JXTA is a representative of P2P system. JXTA is a typical distributed computing model that proposed by Sun Microsystems. JXTA that doesn't require centralized services or resources is adaptable in extreme changes of network organization. MANET(Mobile Ad Hoc Network) is a representative wireless network that is composed of mobile nodes without infrastructure. So MANET establishes the path for the communication of each peers and maintains the newest routing information by exchanging routing information. In this paper, we propose a technique of JXTAMAUET which implements JXTA which is the P2P network system from the wireless network which is becoming the foundation of ubiquitous computing. For the performance evaluation of the JXTAMANET, we use simulation.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.49-51
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• 2003

분산 시스템 아기텍처에 기반한 이동 에이전트는 현재 클라이언트/서버 패러다임을 이어갈 새로운 패러다임으로 인식되고 있다. 이에 따라, 분산 컴퓨팅 환경에 적합한 시스템 구성을 위해 에이전트와 이동 에이전트 등에 대한 많은 연구들이 활발하게 진행되고 있다. 그러나 지금까지 에이전트, 이동 에이전트, 다중 에이전트에 대한 연구들이 기능적인 특성에만 집중되어 왔다. 기능적인 특성은 에이전트와 이동 에이전트가 가지는 기본적인 특성으로서 에이전트들 간의 협동, 협력, 지능을 위한 합리성, 지식 모델링, 추론 방법이다. 그러나 분산 컴퓨팅 환경에서 분산 시스템 구성을 위해 전체 시스템의 성능(Performance), 확장성(Scalability), 안정성(Stability)등이 간과되어서는 안된다. 이런 연구 영역은 기능적인 특성을 다루는 연구영역에 비해 실용적인 면에서 더욱 중요하며, 그 중요성이 점점 더 증가하고 있다. 본 논문은 시스템 성능 향상을 위해 에이전트 간 협력과 협의 레벨의 계층 구조에 중점을 둔다.