• 한국전통조경학회지
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• 제33권3호
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• pp.16-37
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• 2015

본 연구는 석조전 정원 조성 과정과 변천을 사회적 배경에 따른 덕수궁 권역의 변천과 연계하여 분석하였다. 그 결과 정원의 변천 과정을 4단계로 구분하였다. 첫째, 개항기 말인 1896년에서 1914년이다. 1896년부터 1897년까지 경운궁은 법궁으로 조성되어 고종의 거처로 중화전과 석조전이 마련되었다. 석조전 건립 초기에는 브라운이 관여했고, 준공과 정원은 데이빗슨이 마무리했다. 정원 조성 과정에서 중화전 회랑이 훼철되고 돈덕전이 편입되었다. 정원은 중심부에 원형 기식화단과 축선을 겸한 동선을 지닌 단순한 형태였고 독수리 조각상을 세웠으나 곧 철거되었다. 둘째, 1915년에서 1932년으로 17년간 형태가 유지되었던 시기이다. 1911년 대한제국 말기 궁내부를 계승한 이왕직이 1915년에 주전과를 설치하여 덕수궁 내 건물들을 조사했다. 당시의 정원은 1차 조성 형태 요소 중 중심축선은 유지하였지만, 녹지대는 비대칭형으로 하였다. 세부화단은 원형이고 오픈 노트 기법과 경계부 식재를 했고, 세분된 동선을 조성했다. 셋째, 1933년에서 1937년까지로 석조전이 개방된 시기이다. 1932년 석조전을 상설미술관으로 개방하기 위해 많은 건물을 훼철했다. 새로 조성한 정원은 중심축과 연계된 동선 중심에 거북이 조각상이 놓인 직사각형 수반이 있는 형태이다. 넷째, 1938년에서 해방까지로 덕수궁이 공원화된 시기이다. 이왕가미술관을 건립하여 석조전과 브리지로 연결하였고, 정원은 선큰(sunken) 정원으로 변모했다. 분수대, 파고라가 도입되었고 이후 부분적인 변형이 있었으나 현재까지 지속되고 있다. 이처럼 현재 남겨진 석조전 정원은 최초의 모습이 아니며, 따라서 본 연구는 석조전 정원에 대한 언설이 재작성되어야 함을 밝힌 것에 의의가 있다.

• 대한산업공학회지
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• 제38권2호
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• pp.116-124
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• 2012

This paper concerns a joint replenishment problem for a single buyer who sells multiple types of items to end-customers. The buyer periodically replenishes the inventory of each item to a preset order-up-to-level to satisfy the end customers' demands, which may be non-stationary. A joint replenishment policy characterized by variable order-up-to-levels is proposed for the buyer who wishes to minimize the expected cost of operating the retail system. The proposed policy starts each period by calculating the expected cost of ordering and not ordering action based on the information of the current inventory position and forecasted demand for the upcoming period. It then takes advantage of an integer programming model to get a cost effective joint replenishment plan. Computer experiment was performed to test efficiency of the proposed policy. When compared with the most efficient policy currently available, our policy showed a considerable cost savings especially for the problems having non-stationary demands.

• 대한기계학회논문집B
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• 제28권10호
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• pp.1172-1177
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• 2004

The emission control of automobile has been intensified as a part of the countermeasure to decrease air pollution in the world. As the cars with an alternative fuel starts to get into the spotlight, the cars with low emission has been introduced and exhaust gas regulation forced in this country. These days, LPG vehicles, which infrastructure of fuel was already built up, and CNG vehicles are recognized for alternative fuel cars in this country. In this study, the constant volume combustion chamber was manufactured and used for experiments to obtain the combustion characteristics of propane mixture. The combustion characteristics was analyzed, with the change of supply conditions of propane fuel. Inside the combustion chamber, the maximum temperature increase with the initial pressure is going up. The burning velocity also seems to have the same characteristic as the temperature. However, the heat flux do not change much according to the theoretical correct mixture but it changes with the various initial temperature of the combustion chamber.

• 한국정밀공학회지
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• 제22권4호
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• pp.92-98
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• 2005

The learning control develops controllers that learn to improve their performance at executing a given task, based on experience performing this specific task. In a previous work, the authors presented an iterative precision of linear decentralized learning control based on p-integrated learning method for the vertical dynamic multiple systems. This paper develops an indirect decentralized teaming control based on adaptive control method. The original motivation of the teaming control field was loaming in robots doing repetitive tasks such as on an assembly line. This paper starts with decentralized discrete time systems, and progresses to the robot application, modeling the robot as a time varying linear system in the neighborhood of the nominal trajectory, and using the usual robot controllers that are decentralized, treating each link as if it is independent of any coupling with other links. Some techniques will show up in the numerical simulation for vertical dynamic robot. The methods of learning system are shown up for the iterative precision of each link.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.131-136
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• 2002

A computational analysis using Reynolds stress model in FLUENT is conducted to give a clear understanding of the effect of blade loading on the structure of tip leakage flow in a forward-swept axial-flow fan at design condition ($\phi$=0.25) and off-design condition ($\phi$=0.21 and 0.30). The roll-up of tip leakage flow starts near the minimum static wall pressure position, and the tip leakage vortex developes along the centerline of the pressure trough within the blade passages. Near tip region, a reverse flow induced by tip leakage vortex has a blockage effect on the through-flow. As a result, high momentum region is observed below the tip leakage vortex. As the blade loading increases, the reverse flow region is more inclined toward circumferential direction and the onset position of the rolling-up of tip leakage flow moves upstream. Because the casing boundary layer becomes thicker, and the mixing between the through-flow and the leakage jet with the different flow direction is enforced, the streamwise vorticity decays more fast with blade loading increasing. The computational results show that a distinct tip leakage vortex is observed downstream of the blade trailing edge at $\phi$=0.30, but it is not observed at $\phi$=0.21 and 0.25.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.137-140
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• 1993

Electrical properties and thermal annealing effects of $C_{22}$-quinolium(TCNQ) Langmuir-Blodgett(LB) films were studied. Typical current-voltage(I-V) characteristics along the perpendicular direction chow an anomalous behavior of breakdown near the electric-field strength of $10^{6}$V/cm. To see the thermal influence of the specimen, current was measured as a function of temperature(20∼$180^{\circ}C$). It shows that the current increases about 4 orders of magnitude near 60∼$70^{\circ}C$ and remains constant far a while up to ∼$150^{\circ}C$ and then suddenly drops. Such increase of current near 60∼$70^{\circ}C$ seems tn be related to a softness of alkyl chains. Besides the electrical measurements, UV/visible absorption(300∼800 nm) of the thermally annealed sample was measured to see the internal-structure change. It is found that there are four characteristic peaks. At 494 nm, the optical absorption of the thermally annealed specimen at $60^{\circ}C$ starts increase and stays almost constant upto∼ $140^{\circ}C$. And eventually it disappears above $180^{\circ}C$. After heat treatment of the specimen up to $150^{\circ}C$, Uv/visible absorption was measured while cooling.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.313-317
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• 2009

액체추진제로켓엔진의 추진제 공급유로 내 압력보정을 목적으로 설치된 오리피스는 엔진의 시동 및 정지시, 압력파를 발생시키는 원인이 되며 압력파로 인한 저주파 불안정을 막기 위해서는 오리피스의 개도에 따른 동특성의 변화를 살펴볼 필요가 있다. 오리피스의 동특성 변화를 확인하기 위해 오리피스 공급 압력을 급격하게 증가하도록 하였고 오리피스의 개도를 바꿔가며 동적인 압력변화를 측정하였다. 오리피스의 개도가 증가함에 따라 오리피스에 의한 수격현상은 감소하였으며 오리피스 하류의 수력학적 영향이 지배적으로 나타나는 것을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권6호
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• pp.1113-1132
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• 2011

In wireless sensor networks (WSNs), most energy saving asynchronous MAC protocols are custom tailored for unicast communications only. However, broadcast protocols are very commonly used in WSNs for a variety of functionalities, such as gathering network topology information, event monitoring and query processing. In this paper, we propose a novel low-power asynchronous broadcast MAC protocol called Alarm Broadcast (A-CAST). A-CAST employs the strobe preamble that specifies the residual waiting time for the following data transmission. Each receiver goes back to sleep upon hearing the strobe preamble for the residual time duration, to conserve energy and to wake up just before data transmission starts. We compute the energy consumption of A-CAST via rigorous mathematical analysis. The analytic results show that A-CAST outperforms B-CAST, a simple broadcast extension of the well-known B-MAC. We also implement A-CAST on sensor motes and evaluated its performance through real experiments. Our experimental results show that A-CAST reduces the energy consumption by up to 222% compared to the previously proposed protocols.

• 패션비즈니스
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• 제8권6호
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• pp.39-56
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• 2004

At the outset, surrealism starts from pure art, but surrealism has greatly influenced commercial art and fashion circles, more so than any other genre of art. The critical thinking methods of surrealism and its mode of expression continues to influence fashion theory extensively. Even now, surrealism may be found in the designs presented in fashion circles and is still expected for future lines. Surrealism in modern fashion has been reborn, newly integrated and transformed, based on the features of Surrealism paintings. The characteristics of its forms can be found in a combination of modern material, modern design and new skills and the classical items : bodyform molding context of architecture, experimental and sex-appealing of body. Expression was made by borrowing natural motives and recreating natural fabrics while the existing typical idea about clothes was destructed, with the boundary of patterns changed. Expression was also made by mixing items, uniting future images, and using up-to-date functional techniques. This study is significant that up-to-date technological culture expands cyber-space and increases surrealistic expressions by combined heterogeneous materials, thus arousing much interest. The purpose of this study is to determine interrelationship between how surrealism developed and what formative properties those clothes affected by surrealism obtained in the 1990s.

• 한국분말재료학회지
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• 제17권1호
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• pp.52-58
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• 2010

Bulk nanostructured metallic materials are generally synthesized by bottom-up processing which starts from powders for assembling bulk materials. In this study, the bottom-up powder metallurgy and High Pressure Torsion (HPT) approaches were combined to achieve both full density and grain refinement at the same time. After the HPT process at 473K, the disk samples reached a steady state condition when the microstructure and properties no longer evolve, and equilibrium boundaries with high angle grain boundaries (HAGBs) were dominant. The well dispersed alumina particles played important role of obstacles to dislocation glide and to grain growth, and thus, reduced the grain size at elevated temperature. The small grain size with HAGBs resulted in high strength and good ductility.