• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.437-438
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• 2007

본 논문에서는 우리의 일상생활에 많이 이용되고 있는 무선채널의 시변특성 및 확률론적 모델에 대해 고찰한다. 채널의 일반적인 시간영역 및 주파수 영역에서의 선형시변 특성의 물리적인 의미를 고찰하고 마지막으로 확률론적인 채널 특성을 나타내는 상관함수의 의미를 고찰한다.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.145-146
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• 2015

본 논문은 3상 T-type 3-레벨 인버터의 중성점 전압 제어를 위한 예측제어에 관한 연구이다. 최근 인버터의 효율 향상 등의 장점으로 멀티레벨 인버터가 주목받고 있다. 모델예측제어 방식은 물리적 입력 상태를 반영하여 최적의 성능을 제공할 수 있는 제어기법이다. 3-레벨 인버터에서는 전압벡터의 개수가 많아 예측제어기법을 적용하기에는 계산시간이 오래걸리는 단점이 있다. 본 논문에서는 SPWM 방식에 예측저어를 통해 offset 을 주는 방식으로 DC-link단 중성점 전압제어를 하였다.

• Journal of Information Technology and Architecture
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• v.9 no.4
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• pp.443-453
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• 2012

In order to minimize the damage from system failures, systems over various fields are requested to contain the safety-critical features. In this paper, we deliver the considerable issues, especially, in the cyber physical systems that is recently used as a safety-critical system, as well as we propose the model driven architecture based on time as its the important factor. Based on meta-modeling approach, we introduce the time-based architecture which is associated with deadline, transition state, and threshold, and also we work out a design for this by using model driven architecture. We propose a realizable safety-critical architecture by means of showing failure handling components with safety transaction model from the meta-model. In the detailed models and the example, we design a basic safety processing state, a multiple safety processing state, and a compound safety processing state for completing the safety-critical system architecture.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.4
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• pp.235-238
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• 2008

The Water Erosion Prediction Project (WEPP) was initiated in August 1985 to develop new generation water erosion prediction technology for federal agencies involved in soil and water conservation and environmental planning and assessment. Developed by USDA-ARS as a replacement for empirical erosion prediction technologies, the WEPP model simulates many of the physical processes important in soil erosion, including infiltration, runoff, raindrop detachment, flow detachment, sediment transport, deposition, plant growth and residue decomposition. The WEPP included an extensive field experimental program conducted on cropland, rangeland, and disturbed forest sites to obtain data required to parameterize and test the model. A large team effort at numerous research locations, ARS laboratories, and cooperating land-grant universities was needed to develop this state-of-the-art simulation model. The WEPP model is used for hillslope applications or on small watersheds. Because it is physically based, the model has been successfully used in the evaluation of important natural resources issues throughout the United State and in several other countries. Recent model enhancements include a graphical Windows interface and integration of WEPP with GIS software. A combined wind and water erosion prediction system with easily accessible databases and a common interface is planned for the future.

• Geophysics and Geophysical Exploration
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• v.17 no.4
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• pp.242-246
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• 2014

Spectral induced polarization (SIP) is a useful technique, which uses electrochemical properties, for exploration of metallic sulfide minerals. Equivalent circuit analysis is commonly conducted to calculate IP parameters from SIP data. An equivalent circuit model, which indicates the SIP response of rock, has a non-uniqueness problem. For this reason, it is very important to select the proper model for accurate analysis. Thus, this study focused on suggesting a new model, which suitable for the analysis of an anomalous SIP response, such as ore. A suitability of the new model was verified by comparing it with the existing Dias model and Cole-Cole models. Analysis errors were represented as a normalized root mean square error (NRMSE). The analysis result using the Dias model was the NRMSE of 10.50% and was the NRMSE using the Cole-Cole model of 17.03%. Howerver, because the NRMSE of the new model is 0.87%, it is considered that the new model is more useful for analyzing the anomalous SIP data than other models.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.409-411
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• 2002

컴퓨터상의 물체들을 사용자가 원하는 형태로 변형시켜주는 것은 그래픽스에서 흥미로운 과제이다. 본 논문에서는 사용자의 입력에 따라 자연스러운 변형을 보여주는 방법을 제시한다. 단지 컴퓨터 상에서 물체들의 물리적인 성질만 주어진다면, 물리기반 모델링을 이용해서 어떤 물체들에 대해서도 변형에 대한 동작이 가능하다. 본 논문에서 제시한 개선된 변형 모델은 컴퓨터 게임이나 시뮬레이션등에 널리 사용될 수 있을 것이다.

• Geophysics and Geophysical Exploration
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• v.5 no.2
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• pp.93-98
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• 2002

A three dimensional model for the orebody of an operating mine in Korea was constructed by using a program called '3-D Modeler'. The program allows the user to interactively construct a 3-D model of an orebody from its horizontal cross-sections. The 3-D Modeler is easily able to combine and display various spatial data for model construction. The result of modeling is strongly influenced by control points that correlate to the adjacent horizontal cross-sections. The control points are determined by comparing the geometrical shape of the adjacent cross-sections in conjunction with the geological features of the orebody. The resulting model can be evaluated in viewing the constructed object in three dimensional space or more closely evaluated by inspecting the cross-section. The model can iteratively be improved by modifying the shape of the cross-section and by using this new cross-section for the model building.

• Journal of KIISE:Software and Applications
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• v.31 no.11
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• pp.1483-1495
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• 2004

Recently, new computing technologies are emerging from various life environments, as a result of the spread of network environments and the advent of new computing devices. This trend in computing technology is called "Ubiquitous computing" and is being developed to provide a convenient lifestyle through the dynamic integration of physical objects and digital information. The hybrid tag interface suggested in this paper is a usage model that integrates widely used image codes and recently applied RFIDs in various applications. On the basis of this concept, we eventually designed five different models such as Dual, Partial, Relative, Rebind and Discrete types according to their interrelation. In this paper, the characteristics of tag interfaces in the form of image codes and RFIDs are analyzed and the hybrid tag interface is proposed here for more efficient and convenient interface.

• Journal of the Korea Computer Industry Society
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• v.2 no.2
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• pp.219-228
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• 2001

This paper presents the implementation of comparator which are Fail-Safe with respect to faults caused by any single physical defect likely to occur in NMOS and CMOS integrated circuit. The goal is to use it at the Fail-Safe system. First, a new fault model for PLA(Programmable Logic Array) is presented. This model reflects several physical defects in VLSI circuits. It focuses on designs based on PLA because VLSI chips are far too complex to allow detailed analysis of all the possible physical defects that can occur and of the effects on the operation of the circuit. Second, this paper show that these design, which was implemented with 2 level AND_ORor NOR-NOR circuit, are optimal in term of size. And it also present a formal proof that a comparator implemented as NOR-NOR PLA, based on these design, is self-testing with respect to most single faults in the presented fault model. Finally, it discuss the application of the self-testing comparator as a building block for implementing Fail-Safe Adder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.289-302
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• 1991

Laboratory determination of acoustic property for unconsolidated sediment of Kwangyang Bay was carried out. The compressional wave velocity was correlated to other physical properties and sediment textures to establish a geoacoustic model of the bay. The model was compared to the North Pacific continental terrace sediment. Velocity of the bay is systematically lower(0.02-0.04km/s) than that of the North Pacific. Average velocity of the bay is 1.521km/s. The lowest velocity is measured at the southwestern part of the bay. This area coincides with high amount of fine-grained sediment related to slower circulation. The overall tendency is, however, similar to the North Pacific continental terrace sediment.