In the era of the Fourth Industrial Revolution, Various attempts are being made to converge new industries with IT industry to find new growth engines in the field of IT, maximizing efficiency in terms of productivity. 3D printers are also related to this, and various studies have been conducted worldwide to utilize them in the construction industry. At present, there is an active effort to study atypical structures using 3D printers. The most widely used method is the use of glass panels, however, the additional cost of the manufacturing process and thus the overall project cost cannot be ignored. In addition, the construction of the curvature of the existing two-way curved surface in the conventional flat joint method is not suitable for implementing an amorphous shape. In this paper, we propose an optimized shape through Abaqus analysis of various shapes of Space Truss interior using 3D printing technology using polymer.

Systems such as database and socal network systems have been broadly used, and their unexpected failure, with great losses and sometimes a social confusion, has received attention in recent years. Therefore, it is an important issue to find optimal maintenance plans for such kind of systems from the points of system reliability and maintaining cost. However, it is difficult to maintain a system during its working cycle, since stopping works might incur users some troubles. From the above viewpoint, this paper discusses minimal repair maintenance policy with periodic replacement, while considering the random working cycles. The random working cycle and periodic replacement policies with minimal repair has been discussed in traditional literatures by usually analyzing cases for the nonstopping works. However, maintenance can be more conveniently done at discrete time and even during the working cycle in real applications. So, we propose that periodic replacement is planned at discrete times while considering the random working cycle, and moreover provide a model in which system, with a minimal repair at failures between replacements, is replaced at the minimum of discrete times KT and random cycles Y. The average cost rate model is used to determine the optimal number of periodic replacement.

Fast service access involves keeping track of the location of mobile users, while they are moving around the mobile network for a satisfactory level of QoS (Quality of Service) in a cost-effective manner. The location databases are used to keep track of Mobile Terminals (MT) so that incoming calls can be directed to requested mobile terminals at all times. MT reporting cell system used in location management is to designate each cell in the network as a reporting cell or a non-reporting cell. Determination of an optimal number of reporting cells (or reporting cell configuration) for a given network is reporting cell planning (RCP) problem. This is a difficult combinatorial optimization problem which has an exponential complexity. We can see that a cell in a network is either a reporting cell or a non-reporting cell. Hence, for a given network with N cells, the number of possible solutions is  . We propose a biogeography based optimization (BBO) for design of mobile station location management system in wireless communication network. The number and locations of reporting cells should be determined to balance the registration for location update and paging operations for search the mobile stations to minimize the cost of system. Experimental results show that our proposed BBO is a fairly effective and competitive approach with respect to solution quality for optimally designing location management system because BBO is suitable for combinatorial optimization and multi-functional problems.

This paper is one of basic studies for development of fuel rail to secure strength of GDI system. The fuel rail supports high pressure of 200~250bar and stores fuel while reducing pulsation during injection. Therefore, the structural characteristics of the conventional fuel rail was investigated with respect to stress and displacement. Then, the study focused on reducing stress concentration on fuel rail design to enhance the strength of each components. It was found that the maximum stress was not affected to the dimensions of taper lengths and angles of holes for fuel pipe. Also, it was found that the shape of holes for fuel pipe was key factor to reduce maximum stress, and the bridge between injector and mounting holder was effective structure to reduce the stress of injectors and displacement of the fuel rail system.

쌀 소비 촉진과 쌀가공품의 다양화를 위해 쌀가루를 이용한 이소말토올리고당 제조에 대해 연구하였다. 최적 반응 조건을 확립하기 위해서 상업용 효소인 Termamyl 2X, Maltogenase L, Promozyme D2, Fungamyl 800L, Trnasglucosidase L을 사용하였고, 당류는 HPLC-CAD를 이용하여 말토올리고당과 이소말토올리고당을 동시분석하여 제조 조건별로 당의 구성 및 함량을 확인하였다. 액화반응의 최적화 조건을 탐색하기 위해 효소의 농도 (0.025%, 0.05%, 0.075%, 0.1%)와 시간(1 h, 2 h)에 변화를 주어 반응시켰으며, 가수분해 정도를 확인하기 위해 액화액의 환원당 함량을 측정하였다. 그 결과 Termamyl 2X 를 0.075% 첨가하여 2시간 동안 반응하였을 때 환원당 함량이 138.26 g/L로 가장 높았다. 당화·전이반응의 최적화 조건을 확인하기 위해 효소의 종류, 효소농도, 효소반응시간을 달리하여 이소말토올리고 당을 제조하였다. Maltogenase L, Promozyme D2, Transglucosidase L을 동시에 첨가하여 반응시켰을 때 isomaltose와 panose를 많이 생산하면서 총 이소말토올리 고당의 함량이 가장 높게 나타났다. 그리고 효소의 첨가량을 결정하기 위해 각각 농도에 변화를 주어 시간별로 당 함량을 검토하였다. 그 결과, Maltogenase L은 0.0015%, Promozyme D2는 0.05-0.1%, TransglucosidaseL은 0.1%를 첨가하였을 때, glucose의 함량은 감소되고 중합도가 높은 이소말토올리고당의 함량은 증가하는 효과가 있었다. 최적 효소반응시간 결정을 위해 6시간마다 생성물의 변화를 관찰한 결과, 36시간에 총 이소말토올리고당이 75.36 g/L로 가장 높은 것으으로 확인되었다. 최적 조건으로 제조된 이소말토올리고당은 18 brix였고, isomaltose 35.11 g/L, panose 11.97 g/L, isomaltotriose 19.95 g/L, isomaltotetraose 7.46 g/L, isomaltopentaose 1.05 g/L 이 생성되었으며, 총당 중 이소말토올리고당의 비율은 56.37%였다.

The purpose of this study is to experimentally figure out thermal performances of a newly developed wavy patterned heat plates(first heat plates) which are known to have better thermal performances than the conventional heat plates. Three types of products were made with high and low chevron angled plates. The test results show that overall heat transfer coefficients and pressure drops increased with flow rates and chevron angles just like other studies. Another purpose of this study is to find a way to reduce pressure drops while maintaining or even improving the heat transfer characteristics of the first heat plates. Research on optimization of the distribution area on the heat plate to achieve the even fluid distribution was conducted, and then the second heat plates were developed to reflect the research results. Another new three types of products with the second heat plates were manufactured and tested, too. The test results of the second heat plates were compared with those of the first heat plates to find out how the distribution area contributed to the thermal performances of the heat plates. The comparison showed that distribution area optimization could affect thermal performances of the high chevron angled plate positively, but the low chevron angled plate had little effect from the optimization. This is considered to be because the low chevron angled plate itself has a characteristic that the pressure drop is small.

Powder characteristics, such as density, size, shape, thermal properties, and surface area, are of significant importance in the powder bed fusion (PBF) process. The powder required is exclusive for an efficient PBF process. In this study, the particle size distribution suitable for the powder bed fusion process was derived by modeling the PBF product using simulation software (GeoDict). The modeling was carried out by layering sintered powder with a large particle size distribution, with 50 μm being the largest particle size. The results of the simulation showed that the porosity decreased when the mean particle size of the powder was reduced or the standard deviation increased. The particle size distribution of prepared titanium powder by the atomization process was also studied. This study is expected to offer direction for studies related to powder production for additive manufacturing.

본 연구에서는 전 바나듐 레독스 흐름전지(VRFB)에 적용하기 위한 세공충진 음이온교환막의 최적 설계 조건을 도출하고자 하였다. 실험결과를 통해 VRFB 충방전 성능에 가장 지대한 영향을 미치는 막 설계인자는 이온교환용량, 지지체의 기공율 및 가교도임을 확인할 수 있었다. 즉, 상기 인자들에 의해 VRFB의 ohmic loss와 활물질의 crossover가 결정되었다. 또 한 세공충진 음이온교환막의 제조 시 낮은 가교도에서 이온교환용량을 감소시키는 것과 높은 이온교환용량에서 가교도를 증 가시키는 두 가지 방안을 검토하였다. 그 결과 충분히 높은 이온교환용량에서 가교도를 최적화 하는 것이 VRFB 충방전 성능 관점에서 바람직한 것으로 판단되었다.

억새와 같은 초본계 바이오매스로부터 cellulose, hemicellulose, lignin 등 주요성분을 추출하기 위해서는 알칼리 전처리가 효율적이며, 본 연구에서는 수산화칼륨(KOH)을 이용한 전처리 조건을 최적화하였다. 전처리 변수의 최적화는 반응표면분석법(RSM)을 적용하였다. RSM의 변수는 3개였으며, 변수범위는 각각 KOH 0.2∼0.8M, 반응온도 110∼190℃ 및 반응시간 10∼90min 이었다. 억새의 알칼리 전처리를 위한 최적조건은 KOH 농도 0.47M, 반응온도 134℃ 및 반응시간 65min 이었다. 최적 전 처리 조건에 따라 전처리를 수행한 후 고형물의 cellulose 함량은 66.1±1.1% 이었으며, hemicellulose 및 lignin 함량은 각각 26.4±0.4%, 3.7±0.1% 이었다. RMS 모델식에 따라 계산된 예측값은 실제값 대비 95% 범위 내에서 유효하였다. 최종적으로 전처리물을 동시당화발효를 통해 검증한 결과 에탄올 생산 수율은 96% 이었다.

In this study, an algorithm for control of SPD(Suspended Particles Display) on Smart Skin was proposed. The office with SPD located in Jeonju, Jeollabuk-do was modeled and simulated using TRNSYS18. Through simulation, the energy and lighting consumption of building were analyzed The two kinds of control algorithm(SPD and dimming control method for cool energy and lighting energy saving(CASE 1) and improved control method(CASE 2)) were compared. For this research, Two models(with and without SPD and dimming control) were analyzed by comparing the cooling energy and the light energy consumption was reduced 15.1%, and the lightind energy consumption was reduced by 39.2% more than the model without SPD and dimming control. But, at the improved control method(CASE 2) the cooling energy consumption was reduced of more 2.5% and lighting energy consumptions was reduced of more 18.3% than CASE 1. When using SPD and dimming control, lighting energy consumptions showed more sensitive to solar radiation than cooling energy consumptions. As the improved control method(CASE 2) showed more advantageous saving tate than SPD and dimming control metrhod for cool energy and lighting energy saving(CASE 1), it was found that the improved control method (CASE 2) must be utilized in practice for SPD and dimming control.

CKD 추출액은 시멘트공정에서 발생한 폐기물인 CKD를 시멘트 원료로 재사용하기 위해 공정 방해물질로 작용하는 KCl을 추출한 폐수이며, 폐수처리시설 증설 등의 문제로 추출액 무방류 및 이를 재이용하고자 하였다. 이온교환법을 적용하여 KCl을 제거한 결과, 이온교환 후 추출액의 pH는 12.7 에서 pH 2 미만으로 감소하였으며 양이온교환수지의 H+가 이온교환을 거쳐 추출액에 용해되었음을 확인하였다. 이온교환의 선택성에 의해 Ca2+, K+ 순서로 제거되었으며, K+ 이온을 제거하기 위해 접촉시 간의 증가가 필요함을 판단하였다. 이온교환수지와 직접접촉시간이 약 6배 높은 접촉시간을 갖는 회분 식장치에서 연속흐름식장치 대비 4배 높은 K+ 제거 효율을, 7배 높은 Cl- 제거 효율을 확인하였다. 양이온교환수지의 H+가 음이온교환수지의 OH- 대비 1.2배 빠른 교환속도를 가짐을 추출액 pH 변화를 통해 확인하였다.

In this study, the shape optimization of the injector according to fuel and tip was conducted through analytical techniques. As an analysis condition, a flow rate of 0.08 kg / s was applied to the inlet and the outlet was given a condition of 0 Bar. The working fluid for each fuel was applied. As a result of the analysis, it can be seen that the pressure and velocity of model with the modified tip become higher than that of the base model in diesel. Compared with the base model in the case of gasoline, the modified model of the tip was found to have more stable injection when the pressure inside the combustion chamber and the straightness of the fuel were observed. Finally, in case of LPG injector, the same modified tip as gasoline was found to be the more stable injection. On the basis of this study result, the shape parameters of the injector can be inferred.

The purpose of this study was to optimize the rice protein extracted using a response surface methodology. The experiment was designed based on a CCD (Central Composite Design), and the independent variables were the high pressure (X1, 0-400 MPa) and processing time (X2, 0-10 minutes). The results of the extraction content (Y1), residue content (Y2), and recovery yield (Y3) were fitted to a response surface methodology model (R2= 0.92, 0.92, and 0.93, respectively). Increasing the pressure and processing time has a positive effect on the extraction content (Y1), residue content (Y2), and recovery yield (Y3). Therefore, these high-pressure conditions (independent variables) can significantly affect the improvement in rice protein extraction efficiency. Thus, the optimal conditions of X1 and X2 were 400 MPa and 10 min., respectively. Under these optimal conditions, the predicted values of Y1, Y2, and Y3 were 62.93, 57.53 mg/g, and 91.76%, respectively.

This study examined the relative importance and the effective utility of fermented milk by consumers. The questionnaire was developed by an in-depth interview and literature review and was surveyed on-line. Statistical analysis was carried out descriptive analysis, ANOVA, paired t-test, and conjoint analysis using the SPSS package. First, an analysis of the consumption status of fermented milk found that the consumption frequency was 1-2 times/week (36.2%), 3-4 times/week (26.5%). The product choice attributes of fermented milk were found to be the same with ‘taste’ (3.93) and ‘manufacturing date/expired date’ (3.92), rated the highest, followed in order by, ‘sanitary quality’ (3.82), ‘origin of ingredient’ (3.81). Comparative analysis of the importance and satisfaction level of the choice attributes of fermented milk showed that the choice attributes with lower satisfaction compared to importance were ‘taste’, ‘nutrients’, ‘manufacturing data/expired date’, ‘sanitation quality’, ‘price’, ‘manufacturing method’ and ‘certification of quality’ (p<0.001, p<0.01). ‘Price’ and ‘certification of quality’ were the choice attributes of fermented milk classified as ‘Focus Here’ because of its high importance and low satisfaction. The preferred combination of relative importance in choice attributes of the fermented milk was ‘domestic resource’, ‘Eat with spoon’, and ‘none additives’. Therefore, it is believed that sales will increase if dairy companies can improve the ‘price’ and ‘certification of quality’. In addition, the use of domestic ingredients in the development of new fermented milk products in the future could be an important marketing factor in consumer choice.

본 논문에서는 AISC 표준 단면을 설계 변수로 하는 캔틸레버 타입 헬리데크 모델의 유전 알고리즘 최적설계를 소개한다. AISC 표준 단면을 단면 형상별로 분류하고 단면적 순으로 정렬한 후 정수 단면 번호를 부여하여 설계 변수로 최적설계를 수행하였다. 이 과정을 통하여 이산화된 설계 변수를 가지는 최적설계 문제를 해결하기 위해 유전 알고리즘을 적용하였다. 또한, 제약조건으로 허용응력 및 허용응력비 검사 조건을 모두 고려하여 구조물의 구조 안정성을 고려한 설계를 수행하였다. 최적설계 과정중 매 반복계산 마다 수행되는 구조해석 시간을 단축시키기 위해 선형 중첩법을 사용하였고, 이를 통해 구조 해석 시간을 약 75% 감소시킬 수 있었다. 또한 헬리데크 최적설계의 경량 효과를 높이기 위해 부재 그룹 세분화를 하였고, 그 결과를 선행 연구 모델, 기존의 부재 그룹 모델과 비교하였다. 그 결과 선행연구 대비 약 30톤의 부재를 절감할 수 있었으며, 구조적으로도 보다 안전한 헬리데크 설계를 얻을 수 있었다.

정삼투 공정(forward osmosis, FO)은 역삼투 공정(reverse osmosis, RO)에 비해 저압으로 운영되므로 오염 제어, 유지 보수, 막 세정 및 잠재적 에너지 저감 측면에서 큰 이점이 있어 다양한 분야에 적용할 수 있는 기술이다. 특히, 정삼투 공정의 막오염층이 비교적 느슨하고 분산된 특성을 가지므로 역삼투 공정과 달리 물리세정만으로도 충분한 막오염 제어가 가능하다. 하지만 기존 연구들의 경우 정삼투 물리세정에 적합한 세정 유속을 적용하지 않아 최적화 운전을 하지 못했다는 한계가 있다. 따라서 이 연구는 경제적인 에너지량으로 높은 효율의 세정을 보일 수 있는 적절한 유속의 정당성 평가를 목적으로 한다. 정삼투 공정 막오염 실험을 8.54 cm/s 순환 유속으로 유지하고 세 가지 세정유속으로 회복률과 SEC(specific energy consumption) 비교 평가하였다. 이 실험의 결과로 2배속 세정이 3배속 세정의 수투과도 회복률 만큼의 높은 효율을 보 이는 동시에, 2배속 세정이 높은 세정효율 및 경제적인 SEC를 보이는 적절한 유속이라는 것을 확인하였다.

구조물의 진동에 의해 유발되는 사용성, 안정성 저하를 방지하고, 성능을 개선하기 위하여 많은 진동제어시스템이 사용되어 왔다. 제어기 설계가 H2-norm, H∞-norm 으로 분리되어 독립적으로 이루어지다가 LMI 기법에 의하여 보다 효율적인 제어기 설계가 가능하게 되었다. 본 연구에서는 관심지점의 구조물 응답을 특정한 값 이하로 보장한 상태에서 제진장치 구동에 필요한 변수를 최소 화하는 제어알고리듬을 개발하여 능동형뿐만 아니라 수동형제진장치에도 적용하는 방안을 제시하였다. 관심지점의 구조물 응답의 제한은 요구 등가감쇠비와 H∞-norm을 연계하여 구속조건으로 설정하고 목적함수는 제진장치의 이송거리 또는 댐퍼 용량은 H2-norm으 로 표현하는 혼합제어를 구성하였다. 본 연구에서 제안된 혼합제어 기법을 능동질량감쇠기와 등가치환 점탄성 댐퍼가 설치된 구조물에 적용하여 수치적으로 검증하였다. 수치해석결과, 혼합제어문제를 LMI표준형으로 전환하면 능동형, 수동형 제진장치 설계를 보다 용이하게 적용 가능함을 알 수 있었다.

본 연구는 최적의 당화 조건을 구명하기 위해 양파즙과 양파박을 0, 10, 20%로 첨가했다. 처리별로 25, 30, 35℃에서 72시간 동안 당화시켰다. 35℃의 당화 온도에서 처리 24시간 후 양파즙 첨가 20%에서 13.2 ◦Brix, 양파박 첨가 20%에서 19.6 ◦Brix의 당도를 나타내었다. 그러나 관능 평가결과 처리 간에 크게 차이가 나지 않았다. 양파박을 사용한 양파 당화물이 염증 유발물질인 히스타민 방출량을 14% 억제하는 효과를 나타내었다. ELISA 분석 결과 양파당화물이 대조군에 비해 IL-8과 TNF의 방출을 보다 효과적으로 차단할 수 있었다.

We study substrate support structures and materials to improve uptime and shorten preventive maintenance cycles for chemical vapor deposition equipment. In order to improve the rolling of the substrate support, the bushing device adopts a ball transfer method in which a large ball and a small ball are mixed. When the main transfer ball of the bushing part of the substrate support contacts the substrate support, the small ball also rotates simultaneously with the rotation of the main ball, minimizing the resistance that can be generated during the vertical movement of the substrate support. As a result of the improvement, the glass substrate breakage rate is reduced by more than 90 ~ 95 %, and the equipment preventive maintenance and board support replacement cycles are extended four times or more, from once a month to more than four months, and the equipment uptime is at least 15 % improved. This study proposes an optimization method for substrate support structure and material improvement of chemical vapor deposition equipment.

본 연구에서는 메주에서 분리된 C. allociferrii JNO301 을 이용한 최적 홍삼 ginsenosides의 생물전환 조건을 확인한 결과, 1.0% (v/v)의 홍삼 추출물에 탄소원으로서 2.5%(w/ v)의 galactose, 질소원으로서 1.0% (w/v)의 soytone을 첨가 하여 30oC에서 145 rpm으로 8일간 배양을 최적 생물전환 조건으로 확립하였다. C. allociferrii JNO301에 의해 홍삼 추출물에 존재하는 Rb1, Rb2, Rc, Rf가 생물전환되어 F2, Rh1, Rh2, compound O, compound Mc1, compound K 등 의 minor ginsenosides의 함량이 증가되었다.