• IEMEK Journal of Embedded Systems and Applications
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• v.1 no.2
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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.

• The KIPS Transactions:PartB
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• v.9B no.6
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• pp.775-782
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• 2002

As electronic commerce systems have been widely used, the necessity of adaptive e-commerce agent systems has been increased. These kinds of agents can monitor customer's purchasing behaviors, clutter them in similar categories, and induce customer's preference from each category. In order to implement our adaptive e-commerce agent system, we focus on following 3 components-the monitor agent which can monitor customer's browsing/purchasing data and abstract them, the conceptual cluster agent which cluster customer's abstract data, and the customer profile agent which generate profile from cluster, In order to infer more accurate customer's preference, we propose a 2 layered structure consisting of conceptual cluster and inductive profile generator. Many systems have been suffered from errors in deriving user profiles by using a single structure. However, our proposed 2 layered structure enables us to improve the qualify of user profile by clustering user purchasing behavior in advance. This approach enables us to build more user adaptive e-commerce system according to user purchasing behavior.

• Proceedings of the IEEK Conference
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• 1998.10a
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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.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.2 s.25
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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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• v.17 no.4
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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.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.6
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• pp.37-46
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• 2005

In the Web environment with a huge amount of information, Web page access patterns for the users visiting certain web site can be diverse and change continually in accordance with the change of its environment. Therefore it is almost impossible to develop and design web sites which fit perfectly for every web user's desire. Adaptive web site was proposed as solution to this problem. In this paper, we will present an effective method that uses a probabilistic model of DTMC(Discrete-Time Markov Chain) for learning user's access patterns and applying these patterns to construct an adaptive web site.

• Journal of Communications and Networks
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• v.10 no.1
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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.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.33 no.12
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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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• v.40 no.4
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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.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.3
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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.