• 한국산학기술학회논문지
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• 제5권4호
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• pp.331-335
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• 2004

본 논문에서는 반도체 공정 시뮬레이션을 위해 산화, 확산 및 이온 주입 공정을 모델링하고, 효율적인 실행과 상호 연관된 연속 공정의 시뮬레이션이 가능하도록 통합화된 환경을 구축하였다. 점성적 스트레스 모델을 이용한 산화 공정은 유속-압력 알고리즘과 경계요소법을 이용하여 안정된 해를 얻었으며, 선확산과 산화증배 현상이 포함된 확산 공정은 전진해법과 유한요소법을 이용하였다 또한 이온 주입 공정은 TRIM을 기본으로 다양한 공정 조건에 대한 모델이 추가된 몬테카를로 방법을 사용하였다. 편리한 사용자 입력 인터페이스와 그래픽적 출력을 제공하고, 윈도즈의 API함수를 이용하여 PC상에서 적은 메모리로도 빠른 결과를 얻을 수 있도록 하였으며, 객체 지향적인 모듈화로 타 시뮬레이터와의 호환성이 가능하도록 구성하였다.

• 한국정보처리학회논문지
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• 제7권3호
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• pp.891-900
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• 2000

A Visual development framework for embedded system is presented based on virtual prototyping. Embedded systems often are used in life critical situation, where reliability is very important. Time_to_market, correctness, user_friendly_design are another features required for embedded system design. However, embedded systems are today designed with an ad hoc approach that is heavily based on earlier experience with similar products. We believe that new design paradigm is needed and it should be based on the use of formal model and visual system to describe the behavior of the system at a high level abstraction. Virtual prototyping has all the required features. It has the following advantages; correct design, clear interface definition, idea experimentation, increased communication. In this paper, we describe the design and implementation of VIP/Sim(Virtual Prototyping Simulator), a visionary development framework for embedded system design. New feature such as state polymorphism is augmented to the de_facto standard formal language, statechart, for enhanced dynamic modeling. Actual design experience with VIP/Sim is also discussed.

• 환경영향평가
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• 제20권3호
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• pp.357-365
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• 2011

The QUAL2K has the same basic characteristics as the QUAL2E model, which has been widely used in stream water quality modeling; in QUAL2K, however, various functions are supplemented. The QUAL2Kw model uses a genetic algorithm(GA) for automatic calibration of QUAL2K, and it can search for optimum water quality parameters efficiently using the calculation results of the model. The QUAL2Kw model was applied to the Gangneung Namdaecheon River on the east side of the Korean Peninsula. Because of the effluents from the urban area, the middle and lower parts of the river are more polluted than the upper parts. Moreover, the hydraulic characteristics differ between the lower and upper parts of rivers. Thus, the river reaches were divided into seven parts, auto-calibration for the multiple reaches was performed using the function of the user-defined automatic calibration of the rates worksheets. Because GA parameters affect the optimal solution of the model, the impact of the GA parameters used in QUAL2Kw on the fitness of the model was analyzed. Sensitivity analysis of various factors, such as population size, crossover probability, crossover mode, strategy for mutation and elitism, mutation rate, and reproduction plan, were performed. Using the results of this sensitivity analysis, the optimum GA parameters were selected to achieve the best fitness value.

• 조명전기설비학회논문지
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• 제29권11호
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• pp.96-101
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• 2015

In recent years, researches regarding optimal placement of CCTV(Closed-circuit Television) cameras via architecture modeling has been conducted. However, for analyzing surveillance coverage through actual human movement, the application of VA(Video Analytics) function of IP(Internet Protocol) cameras has not been studied. This paper compares two methods using data captured from real-world cameras and data acquired from a virtual environment. In using real cameras, we develop GUI(Graphical User Interface) to be used as a logfile which is stored hourly and daily through VA functions and to be used commercially for placement of products inside a shop. The virtual environment was constructed to emulate an real world such as the building structure and the camera with its specifications. Moreover, suitable placement of the camera is done by recognizing obstacles and the number of people counted within the camera's range of view. This research aims to solve time and economic constraints of actual installation of surveillance cameras in real-world environment and to do feasibility study of virtual environment.

• 한국조경학회지
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• 제22권1호
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• pp.1-16
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• 1994

This paper examines the individual and social values of tour and recreation activities related to the characteristics and attractions of parks in urban area through a questionnaire. The data for this research consists of 2,942 samples based on interviews in sixteen parks in Daegu area. Implications of the findings for urban parks design and tour and recreation policy are discussed. Travel cost method and contingent valuation method are applied essentially. These methods yield a reasonable estimation of the relationship between tour and recreation values of the parks and the visit rate which can be used to estimate demand functions for tour and recreation experiences provided by a site. Semilog-type models can be used to estimate the use of the park. Finally, the tour and recreation value of each park per user-day is estimated by the total experiences of the users. This study is a modest but important step in the investigation of urban parks and recreation site demand and values. Many of the developments in contingent valuation method and travel cost modeling should now be applied to the urban scale parks and recreation sits. Such studies will contribute significantly to the improvement of methodology for tour and recreation values measuring, especially to individual and social benefits for the urban parks, and provide the much needed guidance for the allocation of scarce tour and recreation resources.

• 한국정보통신학회논문지
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• 제13권10호
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• pp.2140-2146
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• 2009

태그는 위치정보가 없기 때문에 리더의 식별자를 위치정보로 사용하지만 비연속적인 심볼형 정보이다. 따라서 태그 이동 궤적간의 근접성을 정의하는 것이 어려우며 사용자 질의 처리시 비효율적이다. 본 논문에서는 태그 위치를 표현하기 위하여 인식공간을 정의하고 인식공간 근접성을 제안한다. 인식공간 근접성은 정적 인식공간 근접성과 동적 인식공간 근접성으로 구성되며 이를 이용하여 태그 궤적 간의 근접성을 측정하고 효율적인 색인을 구축할 수 있다. 제안한 태그 이동 궤적 근접성 함수를 평가하기 위해 태그 색인 기법인 IR-tree와 이동체 색인 기법인 $R^*$-tree를 대상으로 성능평가 실험을 수행하였다.

• 한국수자원학회논문집
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• 제34권2호
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• pp.107-118
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• 2001

본 연구에서는 2차원 동수역학적 수치해석모형을 개발하고, 한강하류부에 적용하였다. 과학적인 천수흐름 거동해석을 위해서 GIS에 기초한 등수역학모형을 구성하였으며, 개발된 모형의 검증을 위해서 모의수행에 의한 결과 값과 현장관측값과의 비교를 수행하였다. 본 연구에서 제시된 수치해석 모형은 Petrol-Galerkin 유한요소법이다. 또한 GIS를 이용한 하천흐름해석기법을 관측 하였으며, 이는 다양한 해석을 통해 직접적으로 사용자의 결정에 도움을 주게 된다. 본 연구의 결과는 다양한 하천, 저수지 그리고 하구의 해석에 관한 지침이 될 수 있을 것으로 사료된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권9호
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• pp.2982-3003
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• 2014

With the explosive deployment of the wireless communications technology, the increased QoS requirement has sparked keen interest in network planning and optimization. As the major players in wireless network optimization, the BS's resource utilization and mobile user's QoS can be improved a lot by the load-balancing technology. In this paper, we propose a load-balancing strategy that uses Coordinated Multiple Points (CoMP) technology among the Base Stations (BS) to effectively extend network coverage and increase edge users signal quality. To use universally, different patterns of load-balancing based on CoMP are modeled and discussed. We define two QoS metrics to be guaranteed during CoMP load balancing: call blocking rate and efficient throughput. The closed-form expressions for these two QoS metrics are derived. The load-balancing capacity and QoS performances with different CoMP patterns are evaluated and analyzed in low-dense and high-dense traffic system. The numerical results present the reasonable CoMP load balancing pattern choice with guaranteed QoS in each system.

• Advances in Energy Research
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• 제7권2호
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• pp.85-100
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• 2020

Distributed energy resources (DERs) are essential for coping with growing multiple energy demands. A microgrid (MG) is a small-scale version of the power system which makes possible the integration of DERs as well as achieving maximum demand-side management utilization. Hence, this study focuses on the analysis of optimal power dispatch considering economic aspects in a multi-carrier microgrid (MCMG) with price-responsive loads. This paper proposes a novel time-based demand-side management in order to reshape the load curve, as well as preventing the excessive use of energy in peak hours. In conventional studies, energy consumption is optimized from the perspective of each infrastructure user without considering the interactions. Here, the interaction of energy system infrastructures is considered in the presence of energy storage systems (ESSs), small-scale energy resources (SSERs), and responsive loads. Simulations are performed using GAMS (General Algebraic modeling system) to model MCMG, which are connected to the electricity, natural gas, and district heat networks for supplying multiple energy demands. Results show that the simultaneous operation of various energy carriers, as well as utilization of price-responsive loads, lead to better MCMG performance and decrease operating costs for smart distribution grids. This model is examined on a typical MCMG, and the effectiveness of the proposed model is proven.

• 한국분말재료학회지
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• 제26권5호
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• pp.369-374
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• 2019

The properties of powder metallurgy products are related to their densities. In the present work, we demonstrate a method to apply artificial neural networks (ANNs) trained on experimental data to predict the bulk density of barium titanates. The density is modeled as a function of pressure, press rate, heating rate, sintering temperature, and soaking time using the ANN method. The model predictions with the training and testing data result in a high coefficient of correlation (R2 = 0.95 and Pearson's r = 0.97) and low average error. Moreover, a graphical user interface for the model is developed on the basis of the transformed weights of the optimally trained model. It facilitates the prediction of an infinite combination of process parameters with reasonable accuracy. Sensitivity analysis performed on the ANN model aids the identification of the impact of process parameters on the density of barium titanates.