• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.107-112
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• 2008

수질오염총량관리제는 오염원에 대한 농도규제 방식에서 탈피하여 수계전체의 환경용량을 감안하여 원하는 목표수질을 유지하기 위해 허용할 수 있는 오염총량을 해당 배수구역에 할당하고 초과량은 적정수준으로 삭감토록 하는 광범위한 유역관리 기반의 수질정책이다. 금강수계에서는 1차 수질오염총량관리 기본계획($2004{\sim}2010$)하에 시행계획 및 이행평가가 진행 중에 있으나, 시행초기부터 현재에 이르기까지 제도정착을 위한 현안 문제점들이 제기되어 왔다. 지자체간 갈등을 줄이고 지역균형발전과 광역적 수질관리정책을 합리적으로 수행하기 위해서는 제기되어온 문제점들이 해결되어야 한다. 본 연구에서는 합리적인 오염배출부하량 산정을 위하여 2007년 청주시의 모든 동단위 오염원자료를 구축하고 오염부하량을 배출특성을 분석하였다. 또한 강우배출특성을 적용하기 위하여 하수 발생유량 실측자료와 오염원자료에 반영된 자료를 기초로 산정한 하수발생유량을 비교분석 하였다. 청주시 지역의 강우배출특성을 고려하여 보다 과학적이고 합리적인 방법으로 오염부하량을 산정함으로써 현상을 보다 정확히 반영하여 수질오염총량관리 시행상의 실용적인 오염부하량 산정 방안을 모색하고자 한다.

• Journal of Digital Contents Society
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• v.15 no.4
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• pp.527-532
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• 2014

Recently, due to the proliferation of mobile smart devices, the inovation of bigdata, which analyzes and processes massive data collected from various sensors implaned in smart devices, expands to LBSs. Many location prediction techniques for moving objects have been studied in literature. However, as the majority of studies perform location prediction which depends on specific applications, they hardly reflect the technical requirements of next-generation spatio-temporal information services. Therefore, this paper proposes the design of general-purpose distributed moving object prediction query processing framework that is capable of performing primitive and various types of queries effectively based on massive spatio-temporal data of moving objects in real-world space networks.

• Journal of Korean Society of Forest Science
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• v.82 no.1
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• pp.34-43
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• 1993

In this paper, the characteristics of cable logging operations are discussed from a standpoint of mechanics. An example of standing skyline operations is used to illustrate the mechanical principles. Using force and moment boundary conditions, the maximum allowable payload was formulated as a function of slope profile, system geometry and operation options. This formulation includes fundamental equations for log drag and single segment mechanics. The catenary link model is the basic assumption in simulating cable segment stretches. In order to demonstrate the solution procedures of the formulation, a computer model was developed. The model uses Secant algorithm to determine the solution of the complex nonlinear equation set. Finally, the computer model was demonstrated using a hypothetical data set.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.3
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• pp.229-236
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• 2008

Recently, multilevel H-bridge inverters have become popular in medium to high power ac drive applications. One of significant advantages of them is low harmonic contents in their input line currents thanks to the transformer with multiple phase-shifted secondary windings. This paper attempts to provide basic guidelines for the design of the phase shifting transformer windings and theoretical analysis of input line current harmonics of H-bridge inverters. The part I provides the derivation of basic relationships between input and output current of the transformer and the relationship between the phase shifting characteristics and design aspects of the transformer.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.3
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• pp.237-245
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• 2008

Recently, multilevel H-bridge inverters have become popular in medium to high power ac drive applications. One of significant advantages of them is low harmonic contents in their input line currents thanks to the transformer with multiple phase-shifted secondary windings. This paper attempts to provide basic guidelines for the design of the phase shifting transformer windings and theoretical analysis of input line current harmonics of H-bridge inverters. The part II is devoted to the analysis of the harmonic characteristics of the input line current, providing mathematical background for the equidistant phase-shifting angle distribution policy for harmonic elimination.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.3
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• pp.1-8
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• 2010

Acoustic tuning of quarter-wave resonator is investigated numerically to suppress combustion instability in liquid rocket engines. A model combustion chamber is adopted. First, basic acoustic characteristics are examined and acoustic damping is pursued by quarter-wave resonators. Next, for frequency tuning of the resonators, thermodynamic properties inside the acoustic resonators are estimated based on the numerical data. Maximum damping capacity is obtained when the resonators are designed to have the optimum length calculated with the properties. But, damping capacity induced by the resonators with the same length is comparable with it.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.150-159
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• 2014

Since the release of mid-term domestic GHG goals until 2020, in 2009, some various GHG reduction policies have been proposed. There are two types of modeling approaches for identifying options required to meet greenhouse gas (GHG) abatement targets and assessing their economic impacts: top-down and bottom-up models. Examples of the bottom-up optimization models include MARKAL, MESSAGE, LEAP, and AIM, all of which are developed based on linear programming (LP) with a few differences in user interface and database utilization. In this paper, we suggest a simplified LP formulation and how can build it through step-by-step procedures.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.46-46
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• 1999

터보분자펌프(turbomolecular pump, TMP)는 각종 연구장비, 반도체 제조장치, 가속기, 핵융합 실험 장치 등 여러 분야에서 가장 널리 쓰이는 고진공 펌프로서 자리잡고 있다. 이런 TMP의 광범위한 사용에도 불구하고 성능평가에 관한 통일된 규격이 마련되어 있지 않다. 국제 규격협회(ISO)의 터보분자펌프 성능평가방법 시안을 토대로 제정중인 KS 규격은 아직 실험적인 근거를 자체적으로 가지고 있지 못하므로 앞으로 각 항목들에 대한 많은 실험이 수행되어야 한다. TMP의 성능을 나타내 주는 항목들 중 배기속도(pumping speed)와 압축비(compression ratio)는 가장 중요한 것들로서 다른 고진공 펌프 및 TMP 상호간의 성능을 비교할 수 있는 기본 항목이라 할 수 있다. 본 실험에서는 종래의 단순 TMP와 큰 기체유량에서도 안정된 배기속도를 유지하는 복합터보분자펌프(compound molecular pump, CMP)의 배기속도와 압축비 및 임계배압(critical backing pressure)을 KS 규격안대로 시험 평가하여 안의 평가방법과 기준의 타당성을 검토하고, 두 가지 다른 방식의 펌프에 적용할 수 있는지를 검토하였다. TMP 및 CMP 흡기구에 표준용기를 부착하고 수소 및 질소 기체를 사용하여 흡기구 압력을 변화시키면서 배기속도 및 압축비를 측정하고 배기구 압력을 변호시키면서 최대압축비 및 임계배압을 측정하였다. 흡기구의 압력측정에는 인출형 전리진공계(EG)를 사용하였고, 배기구의 압력측정은 전기용량의 격막진공계(CDG)와 피라니 진공계로 측정하였다. 진공계는 모두 회전식 점성진공계(SRG)로 교정한 후 사용하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.5
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• pp.101-109
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• 2009

In this paper, a new method, cascade 3 phase IHCML(Isolated H-bridge Cascade Multi-Level) inverter and a control method is proposed by using two 3-phase transformers that have respectively different transformation rates. Vector control technique in which the highest proximity vector has been used is also put into use. With this process, the switching frequency is almost identical with the output fundamental frequency, which makes less switching loss, and the switching frequency of the small volume of the H-bridge that is in charge of small power is highly controlled, which improves the quality of the output voltage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1260-1268
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• 2005

Ladder Diagram(LD) is the most extensively used among PLC standard language for the design of control system. But LD has the disadvantages for data processing and maintenance. On the other hand, the Sequential Function Chart(SFC) graphic language is very powerful for describing the sequential logic control algorithm. SFC is based on flow chart, so control flow understanding is very easy and divergence can possible improving its ability. In this paper, we propose the efficient management elevator system using the action qualifiers and choice divergence. From the result, we confirm the SFC language reduced program memory capacity and processing time is faster than LD language.