• 환경영향평가
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• 제32권6호
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• pp.488-502
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• 2023

생태계서비스 계정은 생태계 공급 기능과 수요, 그리고 그 사이에서 발생하는 실제 서비스 흐름을 측정해야 한다. 흐름을 측정하기 위해서는 공급과 수요 관계를 정의해야 하며, 복잡한 연결 관계를 객관화 할 수 있는 방법론이 필요하다. 국내에서는 생태계서비스에 대한 연구가 다양하게 진행되어 왔으나, 생태계서비스 계정화에 관한 연구는 부족하다. 본 연구의 목적은 환경경제통합계정(SEEA)의 실험적 생태계계정(EEA)에서 연구된 EU 방법론을 적용하여 홍수조절 생태계서비스를 평가하고 이를 토대로 생태계 계정 도입 방안을 모색하는데 있다. 연구수행을 위해 생태계의 유출량 보유 잠재력, 홍수조절에 대한 사회·경제적 수요, 그리고 그 사이의 관계로부터 형성되는 실제 서비스 혜택 흐름을 공간 기반으로 모델링하고 정량화하였다. 홍수조절 생태계서비스 실제 흐름을 산정한 결과, 국내 전체 서비스량은 165,595ha로 산출되었으며 많은 부분이 농경지에 집중되고 있음을 확인할 수 있었다. 향후 국내 홍수조절 서비스 계정 정밀화 도입을 위해서는 토지피복도와 같은 핵심 공간자료가 지속해서 구축 관리되어야 하며, 국가, 지역, 유역 등 다양한 공간 범위에서 적용 가능한 입력자료 및 방법론에 대한 연구가 필요할 것으로 보인다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.20-37
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• 2020

In this paper, we propose a simulation method based on backward simulation and process-oriented simulation to take into account the characteristics of shipbuilding production, which is an order-based industry with a job shop production environment. The shipyard production planning process was investigated to analyze the detailed process, variables and constraints of mid-term production planning. Backward and process-centric simulation methods were applied to the mid-term production planning process and an improved planning process, which considers the shipbuilding characteristics, was proposed. Based on the problem defined by applying backward process-centric simulation, a system which can conduct Discrete Event Simulation (DES) was developed. The developed mid-term planning system can be linked with the existing shipyard Advanced Planning System (APS). Verification of the system was performed with the actual shipyard mid-term production data for the four ships corresponding to a one-year period.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1248-1257
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• 2014

Overhead transmission lines are crucial components in power transmission systems. Well-designed maintenance strategy for overhead lines is required for power utilities to minimize operating costs, while improving the reliability of the power system. This paper presents a maintenance priority index (MPI) of overhead lines for a reliability centered approach. Proposed maintenance strategy is composed of a state index and importance indices, taking into account a transmission condition and importance in system reliability, respectively. The state index is used to determine the condition of overhead lines. On the other hand, the proposed importance indices indicate their criticality analysis in transmission system, by using a load effect index (LEI) and failure effect index (FEI). The proposed maintenance method using the MPI has been tested on an IEEE 9-bus system, and a numerical result demonstrates that our strategy is more cost effective than traditional maintenance strategies.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2022년도 춘계학술발표대회
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• pp.594-597
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• 2022

Recommendation systems are a prominent approach for users to make informed automated judgments. In terms of movie recommendation systems, there are two methods used; Collaborative filtering, which is based on user similarities; and Content-based filtering which takes into account specific user's activity. However, there are still issues with these two existing methods, and to address those, a combination of collaborative and content-based filtering is employed to produce a more effective system. In addition, various similarity methodologies are used to identify parallels among users. This paper focuses on a survey of the various tactics and methods to find solutions based on the problems of the current recommendation system.

• International Journal of Computer Science & Network Security
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• 제21권4호
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• pp.41-46
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• 2021

The article studies the implementation of automation in the education process as a convenient interface of a document management system, on the one hand, which makes it easy to navigate the program, requiring from the user only a small amount of any special skills in working with electronic computers, on the other hand, it provides to the user operational information about all the data of interest to him, taking into account the access rights given to this or that information, stored in the enterprise database.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 추계학술대회
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• pp.167-168
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• 2017

This paper investigates to identify an optimal for analysis of battery behavior in system-level applications such as Battery Energy Storage Systems in Smart Grid infrastructures and Electrical vehicles. At system level applications, it is mandatory to check model for meaningful equivalency and practical ability for extension from unit cell to Battery stack. The investigation of current battery models in relation to their suitability for study and analysis of system level applications of battery helpful for identification of optimal model and it also provides an intuition and direction to develop the most suitable model, if such models are not available already.

• 제어로봇시스템학회논문지
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• 제20권12호
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• pp.1204-1208
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• 2014

As required performance of UAV (Unmanned Aerial Vehicle) becomes more complex and complicated, required positioning accuracy is becoming more and more higher. GPS is a reliable world wide positioning providing system. Therefore, UAV generally acquires position information from GPS. But when GPS is not available such as too weak signal or too less GPS satellites environments, UAV needs alternative positioning system such as network positioning system. RSSI (Received Signal Strength Indicator) based positioning, which is one method of network positioning technologies, determines its position using RSSI measurements containing distance information from AP (Access Point)s. In that method, a selected AP's configuration has strong and tight relationship with its positioning errors. In this paper, for, we additionally account AP's configuration information by adopting DOP (Dilution of Precision) into AP selection procedures and provide more accurate RSSI based positioning results.

• 조명전기설비학회논문지
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• 제25권3호
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• pp.50-64
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• 2011

In this paper, a DC-coupled photovoltaic (PV), fuel cell (FC) and ultracapacitor hybrid power system is studied for building microgrid. In this proposed system, the PV system provides electric energy to the electrolyzer to produce hydrogen for future use and transfer to the load side, if possible. Whenever the PV system cannot completely meet load demands, the FC system provides power to meet the remaining load. The main weak point of the FC system is slow dynamics, because the power slope is limited to prevent fuel starvation problems, improve performance and increase lifetime. A power management and control algorithm is proposed for the hybrid power system by taking into account the characteristics of each power source. The main works of this paper are hybridization of alternate energy sources with FC systems using long and short storage strategies to build an autonomous system with pragmatic design, and a dynamic model proposed for a PV/FC/UC bank hybrid power generation system. A simulation model for the hybrid power system has been developed using Matlab/Simulink, SimPowerSystems and Matlab/Stateflow. The system performance under the different scenarios has been verified by carrying out simulation studies using a practical load demand profile, hybrid power management and control, and real weather data.

• Smart Structures and Systems
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• 제9권1호
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• pp.71-104
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• 2012

In this research, a typical tension-leg type of floating platform incorporated with an innovative concept of underwater tuned liquid column damper system (UWTLCD) is studied. The purpose of this study is to improve the structural safety by means of mitigating the wave induced vibrations and stresses on the offshore floating Tension Leg Platform (TLP) system. Based on some encouraging results from a previous study, where a Tuned Liquid Column Damper (TLCD) system was employed in a floating platform system to reduce the vibration of the main structure, in this study, the traditional TLCD system was modified and tested. Firstly, the orifice-tube was replaced with a smaller horizontal tube and secondly, the TLCD system was combined into the pontoon system under the platform. The modification creates a multipurpose pontoon system associated with vibration mitigation function. On the other hand, the UWTLCD that is installed underwater instead would not occupy any additional space on the platform and yet provide buoyancy to the system. Experimental tests were performed for the mitigation effect and parameters besides the wave conditions, such as pontoon draught and liquid-length in the TLCD were taken into account in the test. It is found that the accurately tuned UWTLCD system could effectively reduce the dynamic response of the offshore platform system in terms of both the vibration amplitude and tensile forces measured in the mooring tethers.

• 한국군사과학기술학회지
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• 제15권4호
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• pp.381-389
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• 2012

In the existing naval combat system, integrated management is done based on subsystems that make up the system. The naval combat system, however, is a large-scale distributed system made up of subsystems of diverse heterogeneous environments. Although each of the subsystems can be easily managed because they are on the same platform, it is extremely difficult to integrate and manage as a single entity all subsystems that make up the naval combat system because the heterogeneous environments and distributed systems have to be taken into account. In fact, there hasn't been a technique available to integrate and manage subsystems that make up the naval combat system, until now. In this paper, the architecture of an integrated management system is designed and implemented to provide the user with various services. Furthermore, a system that can manage subsystems of the naval combat system in an integrated way is developed.