• KIEAE Journal
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• 제6권3호
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• pp.3-10
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• 2006

As environmental problems and water-shortage phenomenon become a global issue, many states look for the effective method to use water resources. So, decentralized rainwater management is recognized as a new water management system that rainwater can be infiltrated and used on-site. But it is little difficult to build a park, lake, and forest for evaporating rainwater in city because the land price of city is very high. In order to build an excellent infiltration system for a dwelling and a park in Korea, KICT has developed Linear infiltration system. This infiltration system is consist of first flush treatment, storage and infiltration, overflow control system. These elements are connected closely and working as a combined system. A storm sewer can be changed by the linear infiltration system. This study is to make design guideline using Linear infiltration system in apartment house. So ATV-DVWK-M13, FLL and present condition of Korean rainwater system were analyzed and the guidelines direction were set up. Through this study, a foundation is prepared to build the decentralized rainwater management of apartment house.

• Journal of Power Electronics
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• 제19권4호
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• pp.1054-1067
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• 2019

This paper systematically investigates the influence of device parameters spread on the current distribution of paralleled silicon carbide (SiC) MOSFETs. First, a variation coefficient is introduced and used as the evaluating norm for the parameters spread. Then a sample of 30 SiC MOSFET devices from the same batch of a well-known company is selected and tested under the same conditions as those on datasheet. It is found that there is big difference among parameters spread. Furthermore, comprehensive theoretical and simulation analyses are carried out to study the sensitivity of the current imbalance to variations of the device parameters. Based on the concept of the control variable method, the influence of each device parameter on the steady-state and transient current distributions of paralleled SiC MOSFETs are verified separately by experiments. Finally, some screening suggestions of devices or chips before parallel-connection are provided in terms of different applications and different driver configurations.

• Advances in Computational Design
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• 제7권3호
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• pp.189-210
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• 2022

Deployable structures have the ability to shift from a compact state to an expanded functional configuration. By extension, reconfigurability is another function that relies on embedded computation and actuators. Linkage-based mechanisms constitute promising systems in the development of deployable and reconfigurable structures with high flexibility and controllability. The present paper investigates the deployment and reconfigurability of modular linkage structures with a pin and a sliding support, the latter connected to a linear motion actuator. An appropriate control sequence consists of stepwise reconfigurations that involve the selective releasing of one intermediate joint in each closed-loop linkage, effectively reducing it to a 1-DOF "effective crank-slider" mechanism. This approach enables low self-weight and reduced energy consumption. A kinematics and finite-element analysis of different linkage systems, in all intermediate reconfiguration steps of a sequence, have been conducted for different lengths and geometrical characteristics of the members, as well as different actuation methods, i.e., direct and cable-driven actuation. The study provides insight into the impact of various structural typological and geometrical factors on the systems' behavior.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.1009-1014
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• 2023

Muon tomography is a useful method for monitoring special nuclear materials (SNMs) such as spent nuclear fuel inside dry cask storage. Multiple Coulomb scattering of muons can be used to provide information about the 3-dimensional structure and atomic number(Z) of the inner materials. Tomography using muons is less affected by the shielding material and less harmful to health than other measurement methods. We developed a muon detector for muon tomography, which consists of a plastic scintillator, 64 long wavelength-shifting (WLS) fibers attached to the top of the plastic scintillator, and silicon photomultipliers (SiPMs) connected to both ends of each WLS fiber. The muon detector can acquire X and Y positions simultaneously using a position determination algorithm. The design parameters of the muon detector were optimized using DETECT2000 and Geant4 simulations, and a muon detector prototype was built based on the results. Spatial resolution measurement was performed using simulations and experiments to evaluate the feasibility of the muon detector. The experimental results were in good agreement with the simulation results. The muon detector has been confirmed for use in a muon tomography system.

• 농업과학연구
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• 제6권1호
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• pp.56-64
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• 1979

고추 건조(乾燥)의 열원(熱源)으로 태양(太陽)에너지를 이용(利用)하기 위(爲)하여 가격(價格)이 저렴(低廉)한 두 종류(種類)의 평판집열장치(平板集熱裝置)를 설계제작(設計製作)하였으며 이의 이용(利用)에 따른 기본적(基本的)인 요소(要素)들을 분석(分析) 검토(檢討)하였고, 고추의 형태(形態)에 따라 건조시험(乾燥試驗)을 수행(遂行)한바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 대전지방(大田地方)에서의 집열기(集熱機)의 적정경사각(滴定傾斜角)은 1년(年)에 2번 조정(調整)할 경우, 하절기(夏節期)에는 약(約) ${\phi}-15^{\circ}$이고 동절기(冬節期)에는 약(約) ${\phi}+15^{\circ}$였다. 1년중(年中) 직달방향계수(直達方向係數)(Rb)는 집열기(集熱機)의 경사각(傾斜角) $33^{\circ}$에서 4월(月) 16일(日)부터 8월(月) 27일(日)까지를 제외(除外)하고는 1이상(以上)이었다. 2. 시험기간중(試驗期間中)의 외기(外氣) 및 각건조실(各乾燥室)의 조건(條件)은 외기(外氣)의 평균(平均) 온습도(溫濕度)가 $25.6^{\circ}C$, 52.6%RH, 대비건조실(對比乾燥室)이 $42.0^{\circ}C$, 74.2%RH였으며, 물가열식(加熱式)에서 가장 높았고 상대습도(相對濕度)는 공기가열(空氣加熱) 건조실(乾燥室)이 가장 낮았다. 3. 고추 건조(乾燥)에서 건조속도(乾燥速度)는 통고추는 물가열식(加熱式)이 2.3배(培)로 가장 빨랐고 다음이 공기가열식(空氣加熱式), 대비구(對比區) 천일노천구(天日露天區)의 순서(順序)였다. 가장 빠른 건조방법(乾燥方法)은 고추를 수평(水平)으로 절단(切斷)하여 물가열식(加熱式) 건조실(乾燥室)에서 건조(乾燥)시켰을 때였다. 4. 고추의 신미성분(辛味成分)인 capsaicine과 적색소(赤色素)인 capsanthine 함량(含量)은 건조과정중(乾燥過程中)에 약간 감소(減少)하였으나 건조제품(乾燥製品)의 질(質)에 영향(影響)을 미치는 정도(程度)가 아니었으며 건조처리별(乾燥處理別)로도 큰 차이(差異)를 보여 주지 않았다.

• Earthquakes and Structures
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• 제19권1호
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• pp.17-28
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• 2020

In this paper, a modified and improved seismic isolation system called suspension columns for seismic isolation was investigated. An experimental study of the proposed isolation method, together with theoretical and numerical analyses, has thoroughly been conducted. In the proposed method, during the construction of the foundation, some cavities are created at the position of the columns inside the foundation and the columns are placed inside the cavities and hanged from the foundation by flexible cables rather being directly connected to the foundation. Since the columns are suspended and due to the gap between the columns and walls of the cavities, the structure is able to move freely to each side thus, the transmitted seismic actions are reduced. The main parameter of this isolation technique is the length of the suspension cable. As the cable length is changed, the natural frequency of the structure is also changed, thus, the desired frequency can be achieved by means of an appropriate cable length. As the experimental phase of the study, a steel frame structure with two floors was constructed and subjected to the acceleration of three earthquakes using a shaking table with different hanging cable lengths. The structural responses were recorded in terms of acceleration and relative displacement. The experimental results were compared to the theoretical and numerical ones, obtained from the MATLAB programming and the finite element software ABAQUS, showing a suitable agreement between them. The results confirm the effectiveness of the proposed isolation method in reducing the seismic effects on the structure.

• 한국정보통신학회논문지
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• 제20권7호
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• pp.1335-1341
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• 2016

철도의 원활한 운행을 보장하기 위하여 신호, 전철전력, 통신, 설비 등 분야별로 독립된 시스템이 구축되어 운영되고 있으나, 각각의 현장 설비가 센싱 데이터를 중앙관제로 전송하는 매체나 프로토콜이 서로 상이하다. 현재 연구개발을 진행하고 있는 실시간 철도안전 관제시스템은 분산된 안전에 관련된 데이터를 통합하여 위험을 예측하고 철도 사고를 예방하기 위한 것으로, 분산되어 있는 안전 관련 데이터를 통합하여 획득하는 것이 필수적이다. 이를 위하여 서로 상이한 매체나 다양한 프로토콜로 전송되는 정보를 기존 어플리케이션의 변경 없이 수용할 수 있는 데이터 변환이 필요하다. 본 연구에서 다양한 방식으로 전송되는 정보를 통합 관리하기 위한 데이터 변환 사례를 조사하고, 기존 방식에 전송기능을 부가하여 일체화한 XML 기반의 프로토콜 변환 방안을 제시하고, 이를 구현하고자 한다.

• 센서학회지
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• 제23권6호
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• pp.368-376
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• 2014

In order to measure the segmental impedance of the body, a bioelectrical impedance measurement system (BIMS) using multi-frequency applying method and two-electrode method was implemented in this study. The BIMS was composed of constant current source, automatic gain control, and multi-frequency generation units. Three experiments were performed using the BIMS and a commercial impedance analyzer (CIA). First, in order to evaluate the performance of the BIMS, four RC circuits connected with a resistor and capacitor in serial and/or parallel were composed. Bioelectrical impedance (BI) was measured by applying multi-frequencies -5, 10, 50, 100, 150, 200, 300, 400, and 500 KHz - to each circuit. BI values measured by the BIMS were in good agreement with those obtained by the CIA for four RC circuits. Second, after measuring BI at each frequency by applying multi-frequency to the left and right forearm and the popliteal region of the body, BI values measured by the BIMS were compared to those acquired by the CIA. Third, when the distance between electrodes was changed to 1, 3, 5, 7, 9, 11, 13, and 15 cm, BI by the BIMS was also compared to BI from the CIA. In addition, BI of extracellular fluid (ECF) was measured at each frequency ranging from 10 to 500 KHz. BI of intracellular fluid (ICF) was calculated by subtracting BI of ECF measured at 500 kHZ from BI measured at seven frequencies ranging from 50 to 500 KHz. BI of ICF and ECF decreased as the frequency increased. BI of ICF sharply decreased at frequencies above 300 KHz.

• 대한조선학회논문집
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• 제57권3호
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• pp.160-167
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• 2020

A two-stroke diesel engine and a propeller normally adopted in large merchant ships are regarded as major ship vibration sources. They are directly connected and generate various excitation components proportional to the rotating speed of diesel engine. Among the components, the magnitude of two excitation components with the same frequency generated by both engine and propeller can be compensated by the adjustment of their phase difference. It can be done by the optimization of propeller assembly angle but requires a number of burdensome trials to find the optimal angle. In this paper, the efficient estimation method to determine optimal propeller assembly angle is proposed. Its application requires the axial vibration measurement in sea trial and the numerical vibration analysis for propulsion shafting which can be substituted by additional vibration measurement after one-trial modification of propeller assembly angle. In order to verify the validity of the proposed method, the phase difference between two fifth order excitation components generated by both diesel engine and propeller of a real ship is calculated by the finite element analysis and its result is indirectly validated by the comparison of axial vibration responses at intermediate shaft obtained by the numerical analysis and the measurement in sea trial. Finally, it is numerically confirmed that axial vibration response at intermediate shaft at a resonant speed can be decreased more than 87 % if the optimal propeller assembly angle determined by the proposed method is applied.

• 한국컴퓨터정보학회논문지
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• 제4권3호
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• pp.67-72
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• 1999

신경회로망은 학습능력과 근사화 능력으로 말미암아 패턴인식 및 시스템제어분야에서 많이 사용되고 있으며, 입력층. 출력층. 하나 이상의 은닉층으로 구성된 네드워크이다. Elman 신경회로망은 J. Elman에 의해 제안되었으며. recurrent network의 형태로 구성되어 있다. Elman 신경회로망은 기존의 신경회로망에 context층을 새로 추가하여, 은닉층의 출력을 context층의 입력으로 피드백 하는 구조로 되어 있다. 본 논문에서는 새로운 형태의 Elman 신경회로망을 제안한다. 제안한 방식은 Elman 신경회로망을 변형한 형태로. 은닉층 뿐 만 아니라 출력층의 출력도 context층으로 피드백 하는 형태이다. 제안한 방식의 유용성을 확인하기 위해 multi target system에 적용한다. 시뮬레이션 결과는 제안한 방식이 기존의 신경회로망 및 Elman 신경회로망 보다 우수한 방식임을 보여 주고 있다.