• 한국정밀공학회지
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• 제24권4호
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• pp.115-122
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• 2007

Recently, remarkable progress has been made in both technology and production of optical elements including aspheric lens. Especially, requirements for machining glass materials have been increasing in terms of limitation on using environment, flexibility of material selection and surface accuracy. In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical GMP process was developed with an eye to mass production of precision optical glass parts by molding press. This GMP process can produce with precision and good repeatability special form lenses such as camera, video camera, aspheric lens for laser pickup, $f-\theta$ lens for laser printer and prism, and me glass parts including diffraction grating and V-grooved base. GMP process consist a succession of heating, forming, and cooling stage. In this study, as a fundamental study to develop molds for GMP used in fabrication of glass lens, we conducted a glass lens forming simulation. In prior to, to determine flow characteristics and coefficient of friction, a compression test and a compression farming simulation for PBK40, which is a material of glass lens, were conducted. Finally, using flow stress functions and coefficient of friction, a glass lens forming simulation was conducted.

• 한국재료학회지
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• 제30권9호
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• pp.489-494
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• 2020

SiC is a material with excellent strength, heat resistance, and corrosion resistance. It is generally used as a material for SiC invertors, semiconductor susceptors, edge rings, MOCVD susceptors, and mechanical bearings. Recently, SiC single crystals for LED are expected to be a new market application. In addition, SiC is also used as a heating element applied directly to electrical energy. Research in this study has focused on the manufacture of heating elements that can raise the temperature in a short time by irradiating SiC-I₂ with microwaves with polarization difference, instead of applying electric energy directly to increase the convenience and efficiency. In this experiment, Polydimethylsilane (PDMS) with 1,2 wt% of iodine is synthesized under high temperature and pressure using an autoclave. The synthesized Polycarbosilane (PCS) is heat treated in an argon gas atmosphere after curing process. The experimental results obtain resonance peaks using FT-IR and UV-Visible, and the crystal structure is measured by XRD. Also, the heat-generating characteristics are determined in the frequency band of 2.45 GHz after heat treatment in an air atmosphere furnace.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 1994년도 제3회 학술강연회논문집
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• pp.21-26
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• 1994

Conventional electroexplosive devices (EED) commonly use a very small metal bridgewire to ignite explosive materials i.e. pyrotechnics, primary and secondary explosives. The use of semiconductor devices to replace “hot-wire” resistance heating elements in automotive safety systems pyrotechnic devices has been under development for several years. In a typical 1 amp/1 watt electroexplosive devices, ignition takes place a few milliseconds after a current pulse of at least 25 mJ is applied to the bridgewire. In contrast, as for a SCB devices, ignition takes place in a few tens of microseconds and only require approximately one-tenth the input energy of a conventional electroexplosive devices. Typically, when SCB device is driven by a short (20 $\mu\textrm{s}$), low energy pulse (less than 5 mJ), the SCB produces a hot plasma that ignites explosive materials. The advantages and disadvantages of this technology are strongly dependent upon the particular technology selected. To date, three distinct technologies have evolved, each of which utilizes a hot, silicon plasma as the pyrotechnic initiation element. These technologies are 1.) Heavily doped silicon as the resistive heating initiation mechanism, 2.) Tungsten enhanced silicon which utilizes a chemically vapor deposited layer of tungsten as the initiation element, and 3.) a junction diode, fabricated with standard CMOS processes, which creates the initial thermal environment by avalanche breakdown of the diode. This paper describes the three technologies, discusses the advantages and disadvantages of each as they apply to electroexplosive devises, and recommends a methodology for selection of the best device for a particular system environment. The important parameters in this analysis are: All-Fire energy, All-Fire voltage, response time, ease of integration with other semiconductor devices, cost (overall system cost), and reliability. The potential for significant cost savings by integrating several safety functions into the initiator makes this technology worthy of attention by the safety system designer.

• 품질경영학회지
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• 제47권3호
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• pp.437-451
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• 2019

Purpose: The purpose of this study is to improve the quality of the PGM system by improving the structure and production process of slip-ring rotary joint for radar. Methods: The improvement measures for each cause are established through failure analysis of broken items. Specifically, changing in the housing to improve the heating system. Changing the transportation method to prevent damage to equipment during transport. Changing work process of the attenuator ring to prevent damage. etc. Results: The results of this study are as follows; improving the heating system reduces heat generated by the attenuator by about 7 degrees and obtain additional temperature margins. Reduction of defect rate because of adding X-band rotary joint run-out measurement test, ESS of slip-ring rotary joint and Transportation improvement(reinforced flight boxes, tube protection, etc). Getting stable VSWR values by improving work process of attenuator overheating due to a bad bonding process. Conclusion: Through this study, improvements were made to slip-ring rotary joint that failed repeatedly for various reasons. As a result of the application of the improvements, the same fault does not occur until now, so we can see that the quality of PGM has improved.

• 융합보안논문지
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• 제22권2호
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• pp.21-26
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• 2022

마스크 착용은 COVID-19 감염을 예방하기 위한 효과적인 방안이다. 적외선 열화상 기반의 온도 측정과 신원 인식 시스템이 기업에서 널리 사용되고 있는 상황에서 마스크 감지를 위한 연구는 필수적이다. 최근 비전분야에 소개된 MTCNN은 객체 인스턴스 세분화를위한 개념적으로 간단하고 유연하며 일반적인 프레임 워크를 제시한다. 본 논문에서는 열적외선 카메라로부터 획득한 열감지영상에서 발열체인 인스턴스에 대해 발열부위의 세그멘테이션을 생성하는 동시에 이미지 내의 오브젝트 발열부분을 효율적으로 탐색하는 알고리즘을 제안한다. MTCNN(Multi-task Cascaded Convolutional Networks) 기법은 바운딩 박스 인식을 위해 기존 브랜치와 병렬로 객체 마스크를 예측하기 위한 브랜치를 추가한 알고리즘이다. MTCNN은 다른 작업으로 일반화하기 용이하다. 본 논문에서는 MTCNN기반 적외선 열영상 검출알고리즘을 제안하여 RGB영상에서 구별할 수 없는 마스크 착용 여부를 탐지하였다.

• 한국조리학회지
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• 제20권2호
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• pp.65-78
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• 2014

본 연구에서는 소스나 수프 등의 기본 재료가 되는 바지락 육수를 제조함에 있어서 바지락 육수의 각종 영양 성분을 적절하게 이용하여 바지락 육수를 만들고자 하였다. 수분 함량은 가열시간이 증가함에 따라 유의적(p < 0.001)으로 낮아졌다. 색도 측정 결과, L값은 S1(31.15)이 가장 높았고, a값은 S5(-0.36)가 가장 높았으며, b값은 S5(0.67)가 가장 높았다. pH는 60분 가열한 S5가 7.35로 가장 낮아 가열시간이 증가시 유의적(p < 0.001)인 차이를 보이며 낮았다. 당도는 S5가 $3.30^{\circ}Brix$로 가장 높았고, S1이 $2.63^{\circ}Brix$로 낮았으며, 염도는 S1이 0.73%로 가장 낮았고 가열시간이 증가시 시료간의 유의적인(p < 0.001) 차이를 보이며 염도가 높아졌다. 무기질 용출량은 Na의 함량이 가장 높으며, 칼륨과, 마그네슘, 칼슘, 철 모두 60분에서 가열한 바지락 육수가 가장 높았으며, 유리 아미노산은 총21종이 검출되고, 필수 아미노산에서는 Arginine이 가장 많이 용출되었으며, 맛난 맛 아미노산에서는 Glygine, 그 밖의 유리 아미노산은 Taurine 가장 많이 검출되었다. 바지락 육수의 특성 차이 검사 결과에서는 시원한 맛과 구수한 냄새는 S4가 가장 강하게 평가되었고, 기호도 검사 결과는 외관, 향, 맛, 뒷맛, 전체적인 기호도 모든 항목에서 40분 가열한 S3가 가장 좋게 평가되었다. 이상의 결과로 볼때 해산물 육수의 경우 simmering 시간을 약 30~45분 이라는 사실을 확인 하였다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.135-135
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• 2017

Greenhouse have been developed to provide the plants with good environmental conditions for cultivation crop, two major factors of which are the inside air temperature and humidity. The inside temperature are influenced by the heating systems, ventilators and for systems among others, which in turn are geverned by some type of controller. Likewise, humidity environment is the result of complex mass exchanges between the inside air and the several elements of the greenhouse and the outside boundaries. Most of the existing models are based on the energy balance method and heat balance equation for modelling the heat and mass fluxes and generating dynamic elements. However, greenhouse are classified as complex system, and need to make a sophisticated modeling. Furthermore, there is a difficulty in using classical control methods for complex process system due to the process are non linear and multi-output(MIMO) systems. In order to predict the time evolution of conditions in certain greenhouse as a function, we present here to use of recurrent neural networks(RNN) which has been used to implement the direct dynamics of the inside temperature and inside humidity of greenhouse. For the training, we used algorithm of a backpropagation Through Time (BPTT). Because the environmental parameters are shared by all time steps in the network, the gradient at each output depends not only on the calculations of the current time step, but also the previous time steps. The training data was emulated to 13 input variables during March 1 to 7, and the model was tested with database file of March 8. The RMSE of results of the temperature modeling was $0.976^{\circ}C$, and the RMSE of humidity simulation was 4.11%, which will be given to prove the performance of RNN in prediction of the greenhouse environment.

• 한국조경학회지
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• 제18권2호
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• pp.111-125
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• 1990

Korea is a nation with poor natural resources. There is a greats need to save resources that are running out in fast face. The purpose of this thesis is to bind the means to save rosources in housing site, especially in highrise apartment. The reason why the high-rise apartments are chosen as a case is 7hat the high-rise is becoming the major form of dwelling in most urban areas. As a tool of saving the ecological way is chosen because ecological energy is free, clean and unlimited. The resources to be saved are divided into two categories, namely energy and non - energy resources as water, land and food. The contents of the thesis are comprised of 4 chapters. The early chaspters are devoted to the understanding of the ecosystem and problems of current energy consumption in the apartment. It is fellowed by the introduction of the hypothesis that can possibly save reouruces. The hypothesis are then transformed into the actual theories through verification, to be established as the new techniques of the site planning. The ecosystem is the functional relationship between the living organisms and their physical surroundings. The living organisms are the plants that produce, animals that consume and bacterias that decompose. They live in the environment which consists of the three worlds of atmosphere, hydrosphere and lithosphere. The whole system is activated by the solar energy that turns the inorganic mallet- into the living organism and back to the inorganic. It is the recycling principle of the ecosystem. The elements of ecosystem that fan be unilimited as the tools of resources -saving are the sun, wind, water, soil, plant and waste. They are unlimited sources of energy. free of pollution and cheap in price. Each of these ecological elements Provide the opportunities that can save the heating fuel, air conditioning energy, water resource, land and food. The ecological approch should be pursued actively in this age of short resources and growing pollution. In the scale of total energy consumption the housing takes the second position next to the industrial use. It is followed by the transportation which shows for less consumption than former two.

• 한국항공우주학회지
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• 제46권8호
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• pp.687-693
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• 2018

본 연구는 능동형 안테나 시스템의 안정적인 임무수행을 위하여 열적 신뢰성을 고려한 방열설계에 관한 연구이다. 능동형 안테나는 송수신부에 고성능의 고발열 소자들이 존재한다. 안테나의 성능 유지를 위해서는 방열설계를 통해 고발열 소자들에서 발생하는 열을 효과적으로 제거하고, 적정한 온도범위에서 동작할 수 있도록 하여야 한다. 능동형 안테나의 송수신부는 고발열부로 액체냉각을 이용한 방열이 효과적이다. 본 연구에서는 능동형 안테나의 열적 성능을 만족하기 위하여 액체냉각 시스템을 포함한 방열설계를 수행하였으며, 이를 수치해석을 통해 분석, 검증하였다.

• 한국생활과학회지
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• 제19권4호
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• pp.745-760
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• 2010

The purposes of this study were to investigate the state of indoor thermal and air environment during winter in the one-room type multi-family houses occupied by university students and to analyze factors which influenced this environment. Field survey was conducted in 10 houses between 30th January, 2009 and 13th February, 2009 which measured indoor thermal and air elements as well kept records of interviews with residents and other related factors. Measured elements were air temperature, relative humidity, as well as concentrations of $CO_2$, CO, TVOC, and PM-10. The results can be summarized as follows. 1) The mean air temperature in each house ranged from 19.3 to $25.3^{\circ}C$, so most houses were not suitable for evaluation criteria($20-22^{\circ}C$). The average $CO_2$ concentration in each house was 965~3259ppm, so most houses exceeded evaluation criteria(1000ppm). The average TVOC concentration in each house were 0.00~1.17ppm, 5 houses exceeded evaluation criteria(0.12ppm). 2) Relative humidity, CO concentration, and PM-10 concentration were suitable for evaluation criteria. Therefore, indoor thermal and air environment during winter in one-room type multi-family housing occupied by university students was found to be generally uncomfortable. Important factor which were found to influence air temperature and the concentration of $CO_2$ were smaller space capacity than general house. Other factors which were found to influence the environment of these houses were the existence of a balcony as well as factors relating to the behavior of occupants such whether or not heating were operated, whether windows were opened, whether fans used, whether occupants smoked or used cosmetics, and whether the space was dusted.