• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.287-292
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• 2006

본 논문은 환경의 변화에 적응하여 지속적으로 서비스들의 협업을 지원하기 위한 통합 시스템으로 커뮤니티 관리 시스템을 제안한다. 이를 위해 커뮤니티라는 메타포를 사용하여 추상화된 레벨로 협업 모델을 정의하고 이를 런타임에 해석하여 물리적 환경의 실질적인 서비스들간의 실행 모델로 전환한다. 본 논문에서 제안한 시스템은 서비스들의 협업과 사용자의 인터랙션을 관리하는 커뮤니티 매니저(CM)와 서비스들의 협업모델을 실행 환경으로 매핑시키는 커뮤니티 프레임워크(CF) 그리고 CM 과 CF 에게 통합된 컨텍스트를 제공해 주는 시츄에이션 매니저(SM)로 구성되어 있다. 이 시스템에서 추상화된 협업 모델은 런타임에 물리적 공간으로 매핑되므로, 동적으로 실행 환경과 사용자의 특성을 인식하고 그에 맞는 협업 목표와 협업 대상을 변경시켜 실행 환경에 맞게 재구성 되는 것이 가능하다. 따라서 제안된 시스템을 통해 특정 환경에 고유하게 구축되던 시스템의 개발 비용에 대한 부담을 절감시키는 효과를 가져올 것으로 기대된다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.407-412
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• 2007

본 논문에서는 IEEE 802.16 OFDMA 시스템에서 단말들의 에너지 절약을 위한 효율적인 상향 링크 자원 할당 알고리즘을 제시한다. 기지국은 각각의 단말들이 상향링크로 데이터를 전송할 수 있도록 상향링크 부프레임에 연속적인 형태의 자원을 할당해 줘야 한다. 이렇게 각 단말들의 에너지 소비를 고려하여 효율적으로 자원을 할당하는 방식은 최적화 문제의 형태로 접근할 수 있다. 본 논문에서는 전체 에너지소비가 최소가 되는 자원 할당 문제를 Multiple Choice Knapsack 문제로 정의하고, 이를 효율적으로 풀 수 있는 준최적화 알고리즘을 제시한다. 준최적화 알고리즘은 전체 에너지 소비가 최소가 되는 각 단말들의 최적의 변조로 부호화 기법을 찾는다. 그리고 성능평가를 통해 준최적화 알고리즘이 채널 상태만을 고려하여 변조로 부호화 레벨을 결정하는 기법에 비해 최대 53%의 성능 이득을 보이는 것을 제시한다.

• Annual Conference of KIPS
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• 2002.04a
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• pp.755-758
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• 2002

보행자 추적은 무인 자동차 시스템, 보안 또는 감시 시스템, 횡단보도 신호제어 시스템 등 실세계의 다양한 응용 분야에서 사용될 수 있다. 본 논문에서는 걸어다니는 보행자의 움직임 정보를 이용하여 다수의 보행자를 추적하는 새로운 방법을 제안한다. 보행자의 움직임 정보는 연속된 두 개의 비디오 프레임간의 그레이 레벨 차를 이용하여 추하고, 이를 통하여 물체를 검출한다. 검출된 물체에는 보행자뿐만 아니라 다른 이동 물체가 포함될 수 있으므로 프로젝션 히스토그램(PH: Projection Histogram)을 생성한 후 보행자 유형을 기반으로 PH를 분석하여 보행자를 검출, 추적한다. 제안된 방법의 성능 평가를 위해서 복잡한 도시 환경 영상에 적용하고 그 성공적인 결과를 보인다.

• The KIPS Transactions:PartA
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• v.12A no.5 s.95
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• pp.451-460
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• 2005

We present a methodology to design energy-efficient data paths using FPGAs. Our methodology integrates domain specific modeling, coarse-grained performance evaluation, design space exploration, and low-level simulation to understand the tradeoffs between energy, latency, and area. The domain specific modeling technique defines a high-level model by identifying various components and parameters specific to a domain that affect the system-wide energy dissipation. A domain is a family of architectures and corresponding algorithms for a given application kernel. The high-level model also consists of functions for estimating energy, latency, and area that facilitate tradeoff analysis. Design space exploration(DSE) analyzes the design space defined by the domain and selects a set of designs. Low-level simulations are used for accurate performance estimation for the designs selected by the DSE and also for final design selection We illustrate our methodology using a family of architectures and algorithms for matrix multiplication. The designs identified by our methodology demonstrate tradeoffs among energy, latency, and area. We compare our designs with a vendor specified matrix multiplication kernel to demonstrate the effectiveness of our methodology. To illustrate the effectiveness of our methodology, we used average power density(E/AT), energy/(area x latency), as themetric for comparison. For various problem sizes, designs obtained using our methodology are on average $25\%$ superior with respect to the E/AT performance metric, compared with the state-of-the-art designs by Xilinx. We also discuss the implementation of our methodology using the MILAN framework.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1138-1147
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• 2012

In this paper, an efficient power control based MF-TDMA resource allocation scheme is proposed for next generation military satellite communication systems. The proposed scheme has the flexibility is used to support heterogeneous terminals with differ in transmission capabilities. The method can be divided into two parts : burst size calculation and burst structure determination. At first, we estimate the link budget taken into account a dynamic satellite link state variation. Then, applicable ACM level and burst size is chosen. In burst structure determination phase, we reorganize the burst structure in time-frequency domain by controlling limited power, bandwidth, time resources. In particular, we compensate the power spectral density among different terminals to integrate them in same transponder, Furthermore, we increase the packing efficiency by controlling the ACM level of the burst in applicable power spectral density range. Simulation results show that the method increase the spectral efficiency and burst packing efficiency. In addition, slot allocation rejection ratio is successfully reduced.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.171-178
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• 2003

Differentiated Services (DiffServ) is a technique to provide Quality of Service (QoS) in an efficient and scalable way. However, current DiffServ specifications have limitations in providing the complete QoS management framework and its implementation model. This paper proposes a policy-based QoS management model that supports DiffServ policies for managing QoS of DiffServ networks. The management model conforms to Model-View-Controller (MVC) architecture, and is based on Enterprise JavaBeans (EJBs) technologies. In our model, high-level DiffServ QoS policies are represented as valid XML documents with an XML Schema and are translated to low-level EJB policy beans in the EJB-based policy server. The routing topology and role information required to define QoS policies is discovered by using SNMP MIB-II, and the QoS policy distribution and monitoring is accomplished by using SNMP DiffServ MIB.

• Journal of Internet Computing and Services
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• v.15 no.3
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• pp.21-30
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• 2014

Hypertension is one of the major causes of death in the world as it is related with cardiovascular or cerebrovascular disease, so it is needed to provide continuos management for blood pressure. This study selected Health Level 7 Fast Health Interoperability Resources (HL7 FHIR) as a bio-signal data exchange service model that can provide constant blood pressure management in the rapidly growing mobile health care environment. The HL7 FHIR framework developed communicates with the IEEE 11073-10407 Personal Health Device (PHD) protocol through the bluetooth Health Device Profile (HDP) between the manager (smart phone) and the agent (hemomanometer) and acquires information about blood pressure. According to the test results, it performed its tasks successfully including hypertension patients' blood pressure monitoring, management on measured records, generation of document, or transmission of measured information. Because in the actual, clinical environment, it is possible to transmit measured information through the TCP/IP protocol, it will be needed to conduct constant research on it and vitalize it in the field of mobile health care afterwards.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.455-468
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• 2008

In this paper, we propose FAS model for establishing trust based on digital certificates in Grid security framework. The existing RBAC(Role Based Access Control) model is extended to provide permissions depending on the users‘ roles. The FAS model is designed for a system independent integrated Grid security by detailing and extending the fundamental architecture of user, role, and permission. FAS decides each user’s role, allocates access right, and publishes attribute certificate. FAS is composed of three modules: RDM, PCM, and CCM. The RDM decides roles of the user during trust negotiation process and improves the existing low level Grid security in which every single user maps a single shared local name. Both PCM and CCM confirm the capability of the user based on various policies that can restrict priority of the different user groups and roles. We have analyzed the FAS strategy with the complexity of the policy graph-based strategy. In particular, we focused on the algorithm for constructing the policy graph. As a result, the total running time was significantly reduced.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.765-768
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• 2012

Recently, the supply ratio of smart devices application has become increasable, utilization of device increases constantly. At the same time, used application is more gentrified. However, using time of devices is decreased. To solve these problems, many research is studying about the hardware/software. One of them is profiling power consumption by process units. The process can be managed, based on measured energy consumption data. These means that it can efficiently use the residual energy. Application at the stage of program design can analyze and used-energy using the trace by considering the low-power can design. In this paper, we studied software-based power-metering framework for android platform. We survey each process-level power consumption measurement techniques, compare advantages and disadvantages of the technique and propose improved measures.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.6
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• pp.488-496
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• 2015

This paper proposes a framework to determine the routes of multiple unmanned aerial vehicles (UAVs) to conduct multiple tasks in different locations considering the survivability of the vehicles. The routing problem can be formulated as the vehicle routing problem (VRP) with different cost matrices representing the trade-off between the safety of the UAVs and the mission completion time. The threat level for a UAV at a certain location was modeled considering the detection probability and the shoot-down probability. The minimal-cost path connecting two locations considering the threat level and the flight distance was obtained using the Dijkstra algorithm in hexagonal cells. A case study for determining the optimal routes for a persistent multi-UAVs surveillance and reconnaissance missions given multiple enemy bases was conducted and its results were discussed.