• Journal of Magnetics
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• 제18권1호
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• pp.65-73
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• 2013

In this paper, design and performance analysis of robust and inexpensive permanent magnet-assisted synchronous reluctance generators (PMa-SynRG) for tactical and commercial generator sets is studied. More specifically, the optimal design approach is investigated for minimizing volume and maximizing performance for the portable generator. In order to find optimized PMa-SynRG, stator winding configurations and rotor structures are analyzed using the lumped parameter model (LPM). After comparisons of stator windings and rotor structure by LPM, the selected stator winding and rotor structure are optimized using a differential evolution strategy (DES). Finally, output performances are verified by finite element analysis (FEA) and experimental tests. This design process is developed for the optimized design of PMa-SynRG to achieve minimum magnet and machine volume as well as maximum efficiency simultaneously.

• 한국구조물진단유지관리공학회 논문집
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• 제7권2호
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• pp.185-191
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• 2003

본 연구에서는 해석적 검토를 수행하여 합성구조물의 열적응답을 예측하고 발생가능한 문제점을 고찰함으로써 합성형구조 실 시공시 효율적인 자료를 제공토록 하였다. 복합구조의 적용에 의한 콘크리트 단면의 감소는 동일한 구성재료와 타설온도를 적용할 경우 최대온도의 발현량을 감소시키는 효과는 거의 없지만, 중앙부와 표면부의 온도차는 크게 감소시킬 수 있는 것으로 판단된다. 한편, 복합구조의 적용은 콘크리트 구조물의 단면감소를 유발하고, 감소율이 상대적으로 큰 단면에서 기설 콘크리트 구조물에 의한 구속작용으로 인장강도를 초과하는 인장응력이 발생된다. 이러한 응력은 Steel Box와 콘크리트 접촉면의 모서리부에 집중되는 것으로 판단된다. 이와같은 구속작용과 응력집중 현상은 복합구조 적용에 따른 온도차 감소효과를 상쇄시키는 것으로 판단된다. 따라서, 복합구조 적용시 이러한 문제점과 관련된 인자들과 단면 등을 고려한 해석적 검토를 통하여 온도응답 및 적절한 대책이 요구된다.

• Korean Chemical Engineering Research
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• 제48권6호
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• pp.791-794
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• 2010

축전식 전기탈이온(Capacitive deionization: CDI) 시스템을 실제공정에 적용하기 위하여 대용량 제작이 가능하며 높은 처리 효율을 갖는 셀 구조 연구가 필요하다. 본 연구에서는 대용량 제작을 위하여 낮은 수압으로 운전할 수 있는 병렬형 구조와 처리효율을 증가시키기 위하여 집중형 유로를 동시에 적용하여 설계하고 성능 평가하였다. 설계한 유로 구조의 유입수 흐름을 확인하기 위하여 유체역학적 모델링이 가능한 COMSOL프로그램을 사용하여 집중형 유로가 형성되는 것을 확인하였고, 염 제거 효율을 확인하기 위하여 단위 셀과 20층으로 용량 증축된 스택을 사용하여 CDI운전을 통한 제거효율을 확인하였다. 그 결과 $210cm^2$ 면적의 단위 셀에서는 18 ml/min의 유량조건에서 1.1 psi의 수압으로 70.8%의 제거효율을 보였으며, 20층으로 용량 증축된 셀에서는 유량을 20배로 늘린 360 ml/min의 유량조건에서 1.3~1.5 psi의 수압으로 75.6%의 제거효율을 확인할 수 있었다. 연구된 유로 설계는 대용량 시스템을 제작하는데 있어서 적합한 병렬형 구조이며 효율적인 탈염을 할 수 있는 집중형 유로로 설계되어 실제공정에 적용할 수 있는 구조임을 확인할 수 있었다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.483-489
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• 2008

Masonry infill walls are frequently used as interior partitions and exterior walls in low- or middlerise RC buildings In the structural design and assessment of structural behaviors of buildings, the infill walls are usually treated as non-structural elements and they are ignored in analytical models. In this study, seismic behaviors of RC frame with/without masonry infill walls were investigated. To this end, the infill walls were modeled as equivalent diagonal struts. Based on analytical results, it has been shown that masonry infill walls can increase the global strength and stiffness of a structure. Accordingly, inter-story drift ratio will be decreased but seismic forces applied to the structure were increased than design seismic load because natural period of the structure was decreased. It is also seen from the analytical results that the inelastic deformation of RC frame with soft story is concentrated on the first story columns and thus, partial damage may have possibility of collapse of system.

• 한국시스템다이내믹스연구
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• 제17권1호
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• pp.5-24
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• 2016

This study structurally analyzes major inefficiency of Korea's healthcare delivery system by utilizing the systems thinking. In particular, the phenomenon of patient's concentrated visits to large hospitals, waste of resource due to competitions between clinics and large hopitals, and the structure of oversupply were visualized using the causal loop diagram. The inefficient structure of healthcare delivery system can be understood more clearly by utilizing the major system archetypes of 'success to the successful', 'tragedy of commons', 'escalation' and 'limits to growth'. This study also finds solution from archetypal structure suggested by Wolstenholme. The inefficient status of healthcare delivery system might be explained by the 'out of control' archetype. In conclusion, the public resources such as the national health insurance need to be acknowledged as the entire achievement. All the participants should cooperate with each other in order to improve the inefficiency of the healthcare delivery system. In addition, the arrangement of incentive system for cooperation, acceleration of health information technology, and development of innovative business models make the sustainable healthcare delivery system.

• JSTS:Journal of Semiconductor Technology and Science
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• 제8권2호
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• pp.121-127
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• 2008

This paper presents design and fabrication of optimized geometry structure of electrostatic inkjet head. In order to verify effect of geometry shape, we simulate electric field intensity according to the head structure. The electric field strength increases linearly with increasing height of the micro nozzle. As the nozzle diameter decreases, the electric field along the periphery of the meniscus can be more concentrated. We design and fabricate the electrostatic inkjet heads, hole type and pole type, with optimized structure. It was fabricated using thick-thermal oxidation and silicon micromachining technique such as the deep reactive ion etching (DRIE) and chemical wet etching process. It is verified experimentally that the use of the MEMS inkjet head allows a stable and sustainable micro-dripping mode of droplet ejection. A stable micro dripping mode of ejection is observed under the voltages 2.5 kV and droplet diameter is $10\;{\mu}m$.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2284-2291
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• 2018

This paper deals with optimum design of surface mounted permanent magnet synchronous motor (SPMSM) for automotive component. For a compact system structure, it was designed as a motor with a 14-pole 12-slot concentrated winding and hollow shaft. The motor is a thin type structure which stator outer diameter is relatively large compared to its axial length and is designed to have a high magnetic saturation for increasing the torque density. Since the high magnetic saturation in the stator core increases the axial leakage flux, a 3-dimensional (3-D) finite element analysis (FEA) is indispensable for torque analysis. However, optimum designs using 3-D FEA is inefficient in terms of time and cost. Therefore, equivalent 2-D FEA which is able to consider axial leakage flux is applied to the optimization to overcome the disadvantages of 3-D FEA. The structure for cost reduction is proposed and optimum design using equivalent 2-D FEA has been performed.

• 한국응용곤충학회지
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• 제40권2호
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• pp.155-196
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• 2001

Basically insect hormones include ecdysteroids (molting hormone), juvenile hormones, and neurohormones comprising neuropeptides and biogenic amines. This article reviewed their chemical structures and biological functions. The active molting hormone is 20-hydroxyecdysone in most insects but makisterone A in some other insects including the honey bee and several phytophagous hemipterans. Most insects use JH III, but lepidopterans JH I and II. Dipterans also use a different JH, so-called JH $B_3$(JH III bisepoxide) and we still do not know the exact chemical structure of JH utilized in hemipterans. Some other insects use methyl farnesoate or hydroxylated JH III analogues as their juvenile hormone. Most diverse pictures can be found in neurohormones (NH), especially in neuropeptides, in terms of their number and structure. There are more than 200 neuropeptides (NP), classified into more than 30 families, which structures have been identified, and more of them are expected to be reported in the near future, partly due to rapid development in molecular biological techniques and in analytical techniques. More than half of them are involved in controlling activity of visceral muscles. But function (s) of many NPs are not clarified yet, even though their amino acid sequences have been identified. It is partly due to the fact that a single NP may have multiple functions. Another interesting point is their gene structure, having many number of independent, active peptides in one gene, apparently working for similar or totally different functions. NH also includes amines, such as octopamine, dopamine, serotonin, etc. From now on, investigation will be concentrated on identifying their function (s) and receptors, and on possibilities of their utilization as control agents against pest insects.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.403-408
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• 2001

Structure-borne noise and vibration is one of the main complaints of home appliances such as refrigerators, washing machines, air conditioners, etc. There have been many efforts to reduce the emitting noise and vibration. Mostly the efforts have been concentrated to optimize the mounts shape and its material properties realizing that the vibration power is mainly transmitted to the structure via mounts. It is known that softer mounts have the better vibration isolation effect. But mounts have another important function in addition to the vibration isolation. That is to support the motor and compressor safely. Thus mounts should be stiff enough to resist the supporting items. But the two properties, stiff and soft, are contradict each other. So the designer should compromise the two complicity properties properly in between. Noticing that, motors and compressors themselves are very quite until they are connected to the base structure via mounts, wire connecting idea was proposed in this work. Instead of using conventional mounts, as shown in Fig 4, compressor was mounted using six wires as shown in Fig 5. Since wire is very flexible in bending but stiff in tension, we can realize the ideal mount design requirements, stiff enough to support and soft enough to isolate vibration power. The suggesting idea was tested with an air conditioner outdoor unit.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제24권3호
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• pp.17-27
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• 2018

Purpose: This study aims to examine spatial characteristics of emergency department Chronologically through case studies; and to consider the social implication of these spatial changes. Methods: In this study, a total of eight emergency departments, one for each period, were selected in order to analyze the spatial characteristics. The spatial maps of Space Syntax were employed for analyzing case studies. Results: The spatial configuration of emergency department has been changed from five or more emergency department specialties to four or less specialties such as psychiatric, pediatrics, emergency, and trauma. In the case of care initiation area, the concentrated arrangement mode was switched from the distributed arrangement mode. The spatial maps indicate that it can be seen that the tree structure changes to an annular structure emphasizing the connection between the spaces in the emergency department. This shows that the space efficiency, safe, visual control and flexibility in the planning of the emergency department are important factors affecting the spatial structure of the emergency department. Implications: In the future, it is expected that Korean emergency department will be more focused on efficiency, safe, visual control, and flexibility in the planning as in the case studies of the United States.