• 대한임베디드공학회논문지
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• 제1권2호
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• pp.73-81
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• 2006

The home network is generally separated from the Internet, as it is made up of a private network due to security issues and the lack of IPv4 addresses space. Also, a user may want to move from a terminal to another terminal connected in the home network during communicating with people outside the home. In this case, people connected in the Internet, or another home network could not communicate the user at the home. These limitations prevent a SIP-capable device connected in the home network from communicating with another SIP-capable device connected in the Internet or the outside of the home network. To overcome the limitations, This paper proposes the Adaptive SIP Application Server System as a software architecture that a user inside of the home can communicate with people outside of the home when the home is composed of a private IP-based network. Moreover, the proposed architecture provides the session mobility that allows the user to maintain a media session even if changing the terminal inside of the home during the session established. The proposed system was implemented over a home server device which acts functionality as a connection point for transmitting IP packets between a home network and the Internet.

• 정보처리학회논문지B
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• 제9B권6호
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• pp.775-782
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• 2002

전자상거래 시스템의 보급이 활성화되기 시작하면서 사용자의 구매 행위에 적응형으로 대처하는 지능형 전자상거래 에이전트의 필요성이 증대되고 있다. 이와 같은 적응형 전자상거래 에이전트는 사용자의 구매 행위를 모니터하면서, 각 분야별 고객의 구매 행위를 자동 분류하고, 분류된 각 클러스터로부터 사용자의 취향을 학습하는 하는 기능을 필요로 한다. 이러한 기능을 가지는 적응형 전자상거래 에이전트를 구축하기 위해서 본 논문에서는다음 3가지 부분에 중점을 두고 시스템을 설계하였다. 첫째, 사용자의 구매 행위를 포괄적으로 모니터하여 사용자 행위로 추상화하는 모니터 에이전트, 둘째, 고객 구매 행위 데이터로부터 유사한 분야 구매 데이터들로 클러스터 하는 개념적 클러스터 에이전트, 셋째, 각 클러스터로부터 사용자 프로파일을 구축하는 사용자 프로파일 에이전트를 중심으로 설계하는 방안을 제안하고 있다 특히, 본 논문에서는 보다 정확한 고객 구매 행위를 학습하기 위해서 개념적 클러스터링 방식과 귀납적 기계학습 방식을 적용하는 2단계 구조를 제안하고 있다.이와 같은 구조는 여러 분야의 상품을 구매한 정보로부터 사용자의 다중 취향을 학습할 때발생하는 문제를 해결함으로, 사용자 프로파일을 정확하게 구축할 수 있는 장점이 있다. 이러한 정확한 사용자 프로파일을 기반으로 사용자에게 보다 적절한 정보를 제공하는 적응형 전자상거래 시스템을 만들 수 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.7-10
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• 1998

In implementing real time video on demand(VOD), the increase of user on internet causes a network traffic congestion. In this paper, we programmed a CGI able to login in VOD home for limiting the number of user in solving the problem, and also applied and adaptive multimedia synchronization technique for controlling video and audio data in a network. In addition, a real time multimedia player was designed and implemented in a personal computer operating at Window95/98/NT.

• 한국군사과학기술학회지
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• 제9권2호
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• pp.96-102
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• 2006

In this paper, the design, construction and basic characteristics of an electronically adaptive array antenna for the GPS receiver is described. The susceptibility of the GPS signals to the interference is of concern to the GPS user community. Because of the low received power of the GPS signals, outages can easily occur due to the unintentional interference and the easily obtainable low cost GPS jammer denying access to the GPS signals. We propose a technique of the adaptive array antenna that detects the GPS interference sources and controls the null beam pattern only toward the jamming sources to acquire GPS navigation data after acquisition and tracking of the GPS signals.

• Smart Structures and Systems
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• 제17권4호
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• pp.611-629
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• 2016

This study presents a new approach of surrogate modeling for time-consuming finite element analysis. A surrogate model is widely used to reduce the computational cost under an iterative computational analysis. Although a variety of the methods have been widely investigated, there are still difficulties in surrogate modeling from a practical point of view: (1) How to derive optimal design of experiments (i.e., the number of training samples and their locations); and (2) diagnostics of the surrogate model. To overcome these difficulties, we propose a sequential surrogate modeling based on Gaussian process model (GPM) with self-adaptive sampling. The proposed approach not only enables further sampling to make GPM more accurate, but also evaluates the model adequacy within a sequential framework. The applicability of the proposed approach is first demonstrated by using mathematical test functions. Then, it is applied as a substitute of the iterative finite element analysis to Monte Carlo simulation for a response uncertainty analysis under correlated input uncertainties. In all numerical studies, it is successful to build GPM automatically with the minimal user intervention. The proposed approach can be customized for the various response surfaces and help a less experienced user save his/her efforts.

• 전자공학회논문지CI
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• 제42권6호
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• pp.37-46
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• 2005

다양하고 많은 양의 정보가 존재하는 웹 환경에서 웹 사이트를 방문하는 사용자의 접근패턴도 매우 다양하며, 웹 환경의 변화에 따라서 이러한 접근패턴은 계속 변화한다. 이러한 이유로, 웹 사이트 개발자가 사전에 사용자의 욕구에 완벽하게 부합하는 완벽한 사이트를 개발하기란 사실상 불가능하다. 이에 대한 해결방안으로, 웹 사이트에 대한 사용자 접근 패턴을 학습해서 웹 사이트의 구조나 외형을 자동적으로 개선시켜 나가는 적응형 웹 사이트 (Adaptive Web site)가 제시되었다. 본, 논문에서는 DTMC(Discrete-Time Markov Chain)에 의거한 확률적 모델을 이용하여 적응형 웹 사이트 구축에 필요한 사용자 접근패턴을 학습하고 이를 적용하기 위한 효과적인 방법론을 제시한다.

• Journal of Communications and Networks
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• 제10권1호
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• pp.28-37
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• 2008

In this paper, we investigate the problem of minimizing the average transmission power of users while guaranteeing the average delay constraints in time-varying uplink channels. We design a scheduler that selects a user for transmission and determines the transmission rate of the selected user based on the channel and backlog information of users. Since it requires prohibitively high computation complexity to determine an optimal scheduler for multi-user systems, we propose a low-complexity scheduling scheme that can achieve near-optimal performance. In this scheme, we reduce the complexity by decomposing the multiuser problem into multiple individual user problems. We arrange the probability of selecting each user such that it can be determined only by the information of the corresponding user and then optimize the transmission rate of each user independently. We solve the user problem by using a dynamic programming approach and analyze the upper and lower bounds of average transmission power and average delay, respectively. In addition, we investigate the effects of the user selection algorithm on the performance for different channel models. We show that a channel-adaptive user selection algorithm can improve the energy efficiency under uncorrelated channels but the gain is obtainable only for loose delay requirements in the case of correlated channels. Based on this, we propose a user selection algorithm that adapts itself to both the channel condition and the backlog level, which turns out to be energy-efficient over wide range of delay requirement regardless of the channel model.

• 대한건축학회논문집:계획계
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• 제33권12호
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• pp.29-39
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• 2017

The building skins are important architectural elements in both functional and aesthetical aspects. This study focuses on developing a responsive facade with autonomous opening and closing behaviors in accordance with environmental conditions and user requirements for natural ventilation for the office building. The pneumatic ETFE panels are applied as the skin materials taking advantage of the efficiency of the inflatable skin of lightness, architectural performance and sustainable material properties. The biomimetic design methodology is taken for its innovative and visionary concept for the facade design. The interpretation of the building facade in analogy to natural organisms delivers functional and aesthetic characters. By exploring the structural movements of the plant pores, the facade control is developed to be autonomous by the parameter values. The facade opening and closing configurations are derived through parametric modeling and visualization programming. Through the application of this study, expected results are to improve user comfort and energy efficiency.

• ETRI Journal
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• 제40권4호
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• pp.483-498
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• 2018

Nowadays, with progresses in robotic science, the design and implementation of a mechanism for human-robot interaction with a low workload is inevitable. One notable challenge in this field is the interaction between a single human and a group of robots. Therefore, we propose a new comprehensive framework for single-human multiple-robot remote interaction that can form an efficient intelligent adaptive interaction (IAI). Our interaction system can thoroughly adapt itself to changes in interaction context and user states. Some advantages of our devised IAI framework are lower workload, higher level of situation awareness, and efficient interaction. In this paper, we introduce a new IAI architecture as our comprehensive mechanism. In order to practically examine the architecture, we implemented our proposed IAI to control a group of unmanned aerial vehicles (UAVs) under different scenarios. The results show that our devised IAI framework can effectively reduce human workload and the level of situation awareness, and concurrently foster the mission completion percentage of the UAVs.

• 대한전기학회논문지:전력기술부문A
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• 제51권3호
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• pp.143-152
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• 2002

Frequency is regarded as one of most important indices for the operating power systems. Several digital techniques for measuring frequency have been presented in the last decades. This paper proposes a design and implementation an adaptive scheme using phase angle difference calculation fort frequency measuring in power system. The advantages of the proposed technique are demonstrated by fault signals from EMTP simulation and user defined arbitrary signals by Excel program. The proposed technique is compared with the conventional methods. Performance teat results indicate that the proposed technique provides accurate measures in pretence of noise and harmonics and in case faults and is suitable for measurement near-nominal, nominal. and off-nominal frequencies. We can see that It will be useful in microprocessor based relays and digital metiers that need to measure power system frequency.