• Journal of Biosystems Engineering
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• 제15권4호
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• pp.310-318
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• 1990

The amount of grain loss incurred during harvesting operation through the chaff-outlet of combine may not be negligible. To minimize this grain loss and optimize condition of combining, it may be necessary that the amout of chaff-outlet loss dependent on varying crop condition is to be estimated as exactly as possible. This study was thus intended to develop the monitor that could indicate the amount of grain lost through the chaff-outlet of combine during haravesting operation, and to find out driving and operating method of combine that could reduce chaff-outlet loss. In the study(1), the frequency distributions of each sound generated by the impact of kernels and chaff, the sound generated by the impact of the mixture of kernels and chaff, and vibration or noise created by the combine engine and other moving parts were investigated experimentally. Based on the results of frequency analyses, the loss monitor was developed which could measure the impact sound of paddy kernels that could be distinguished from those of other threshing products through chaff-outlet, and from vibration or noise created by the combine engine and other moving parts. Also in this study, detecting capability of monitor was tested by comparing the amount of grain lost through chaff-outlet with the amount of grain detected by the loss monitor, and changes in chaff-outlet grain loss on the increase of traveling speed, location of chaff-outlet loss control plate and variety of paddy rice were measured using the loss monitor. The monitor developed in this study efficiently measured the amount of grain lost through the chaff-outlet of combine. It was found that the chaff-outlet grain loss ratio was affected greatly by the variety of paddy rice, the location of chaff-outlet loss control plate and traveling speed of combine.

• 한국정보과학회논문지:데이타베이스
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• 제30권1호
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• pp.41-51
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• 2003

시간에 따라 변화하는 공간 속성을 다루는 시공간 데이터베이스는 이동 통신 환경에서 위치 기반 서비스를 제공하기 위한 중요한 연구 분야이다. 이동 통신, 교통 관리 그리고 군사 목적의 지휘 통제 시스템 등의 다양한 영역에서 시공간 데이터의 효율적인 관리가 요구되고 있지만, 지속적인 위치 변화로 인한 객체들의 정확한 위치 정보를 데이터베이스에 유지하는 것은 어렵다. 본 논문에서는 다중 버전 B-트리 기반의 $B^{st}$ -트리 색인 구조를 제안 한다 $B^{st}$-트리는 이동 객체들의 퀘적에 대한 효율적인 이력 및 미래 영역 질의를 지원할 수 있다. 또한 동적 버전 관리 알고리즘을 통하여 항상 일정한 질의 처리 성능이 유지될 수 있도록 객체들의 이동 형태에 따라 버전을 유지한다. 그리고 다양한 실험을 통하여 본 논문에서 제안된 색인 방법의 유용성을 보인다.

• 대한기계학회논문집B
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• 제25권10호
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• pp.1392-1399
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• 2001

The flow fields inside a molten Zn pot of continuous hot-chip galvanizing process were investigated experimentally. With varying several parameters including the strip speed Vs, flow rate Q of induction heater. scrapper location and baffle configuration, instantaneous velocity fields were measured using a PIV velocity field measurement technique. Inside the strip region, counter-clockwise rotating flow is dominant. The general flow pattern inside the strip region is nearly not influenced by the strip speed Vs, flow rate Q and the scrapper location. In the exit region, the flow separated from the moving strip due to the existence of a stabilizing roll ascends to the free surface, for the cases of no scrapper and scrapper detached form the roll. On the other hand, the ascending flow to the free surface is decreased, as the flow rate Q of induction heater increases. By installing a baffle around the uprising strip, the flow moving up to the stabilizing roll decreases. In addition, B-type baffle is better than A-type baffle in reducing speed of flow around the stabilizing rolls. However, the flow ascended to the free surface is largely influenced by changing the flow rate Q, and the scrapper location, irrespective of the baffle type.

• 대한인간공학회지
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• 제28권4호
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• pp.147-154
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• 2009

The tactical computer is currently being developed and installed in armored vehicles and tanks for reinforcement. With the tactical computer, Korea Army will be able to grasp the deployment status of our forces, enemy, and obstacles under varying situations. Furthermore, it makes the exchange of command and tactical intelligence possible. Recent studies showed that the task performance is greatly affected by the user interface. The U.S. Army is now conducting user-centered evaluation tests based on C2 (Command & Control) to develop tactical intelligence machinery and tools. This study aims to classify and regroup subordinate menu functions according to the user-centered task performance for the Korea Army's tactical computer. Also, the research suggests an ergonomically sound layout and size of main touch buttons by considering human factors guidelines for button design. To achieve this goal, eight hierarchical subordinate menu functions are initially drawn through clustering analysis and then each group of menu functions was renamed. Based on the suggested menu structure, new location and size of the buttons were tested in terms of response time, number of error, and subjective preference by comparing them to existing ones. The result showed that the best performance was obtained when the number of buttons or functions was eight to conduct tactical missions. Also, the improved button size and location were suggested through the experiment. It was found in addition that the location and size of the buttons had interactions regarding the user's preference.

• 멤브레인
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• 제4권1호
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• pp.1-8
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• 1994

There are growing needs to produce relatively high purity(99.0% or higher) oxygen at low cost. For small scale production, both pressure swing adsorption(PSA) and membrane process are competitive and less expensive or more convenient than well known cryogenic fractionation technology. A continuous membrane column(CMC) combined with a PSA oxygen generator can be employed to produce high purity oxygen continuously. The oxygen enriched gas generated by a PSA unit, with a concentration of 93~94%, is fed to the CMC that consism of three modules of poly(imide) hollow fibers. Several experiments were conducted by varying parameters, such as feed flow rate, transmembrane pressure drop, stage cut, and feed location in order to obtain a high oxygen concentration above 99.0%. A two-series unit mode was also employed with CMC operation to optimize the given membrane area.

• 산업경영시스템학회지
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• 제24권66호
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• pp.37-45
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• 2001

Because the structure of the economy is being changed from product-oriented and company-centered economy to service-oriented and customer-centered economy, and the market competition is varying with the competition of non-price factors, the importance for customer service of logistics system is being increased. Thus, the level of customer service should be represented as an element of the logistics decision and the facility location decision. The level of customer service provided by logistics system has an effect on customers\` purchase decisions, hence on the market demand. That is, the market demand is elastic for customer service as it is influenced by product price. Considering the effect of customer service on demand, this study develops the market area which each facility will serve. That area is circular, and distance norm is considered Euclidean and Rectilinear (or Manhattan) distance norm. The market demand for product at a particular area is affected by the level of customer service that facility provides, and the relationship between the market demand and the level of customer service is represented with a mathematical function.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.33-36
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• 2007

Acoustic holography exhibits the spatial distribution of sound pressure in time or frequency domain. The obtained picture often contains far more than what we need in practice. For example, when we need to know only the locations and overall propagation pattern of sound sources, a method to show only what we need has to be introduced. One way of obtaining the necessary information is to use envelope in space. The spatial envelope is a spatially slowly-varying amplitude of acoustic waves which contains the information of sources' location. A spatial modulation method has been theoretically developed to get a spatial envelope. By applying the spatial envelope, not only the necessary information is obtained but also computation time is reduced during the process of holography. The spatial envelope is verified as an effective visualization scheme in time domain by being applied to complicated sound fields.

• 터널과지하공간
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• 제7권4호
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• pp.334-340
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• 1997

Alpha center theory which was first proposed by Stefanescu has been proved to be effective for the detection of the location of the conductive orebody. A numerical forward modeling was conducted to verify the effectiveness of this method. Field works were carried out along the three profiles in two different areas for the purpose of finding fractured zone which might be accompanied with the presence of the groundwater. And the results were modeled by alpha center method, which was later testified by wellproven 2-dimensional finite difference inversion scheme. Field data could be successfully modeled with this alpha center algorithm, especially for the smooth-varying resistivity models. For the abrupt change of the resistivity values, the alpha center coefficients have a tendency to be negative to simulate the steep resistivity gradients. This method is quite simple and easy for the future applications. The numerical calculation can be performed very quickly with the personal computers.

• Journal of Chest Surgery
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• 제15권2호
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• pp.183-187
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• 1982

Pulmonary arteriovenous fistula is a congenital vascular malformation In the lung, various synonyms including Pulmonary cavernous vascular malformation, Pulmonary arteriovenous aneurysm, Cavernous hemangioma of the lung0 Pulmonary telangiectasia, Pulmonary hamartoma, etc. The pathogenesis of its symptoms is that unoxygenated, desaturated arterial blood enters into the pulmonary venous system directly. Recently we have experienced one case of the pulmonary arteriovenous fistula which was diagnosed as the pulmonary cystic lesion of the lung preoperatively in 20 years old, 61 kg, male patient. Operation was revealed well circumscribed cystic lesion filled with blood, subpleural and anterior mediobasal location, and bright red colored aspirates on two times needle aspirations. Microscopic finding shows ill circumscribed vascular lesion composed of varying sized blood vessels with irregular thickening of wall and final pathological diagnosis is Pulmonary Arteriovenous Fistula. Basal segmentectomy was done and the patient shows good postoperative course.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.701-706
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• 2001

This study is aimed to investigate on the structural properties(like as strength, failure mode, ductility) of beams with multiple openings reinforced with steel tube of circular. The main parameters are follows ;1)location of openings, 2)the number of opening, 3) existence of opening or not. When the locations of opening are respectively maximal moment zone, maximal shear zone, co-existence zone of moment and shear, the specimen with opening at maximal moment zone is not less than that without opening in terms of strength and ductility. The specimens with opening at shear zone and both zones are expected to carry the structural performance corresponding to beam without opening by varying the number and reinforcing method of opening.