• Journal of Korean Society for Quality Management
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• v.27 no.2
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• pp.112-125
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• 1999

In a robust regression model, it is typically assumed that the errors are normally distributed. However, what if the error distribution is deviated from the normality and the response variables are not completely observable due to censoring? For complete data, Kim and Lai(1998) suggested a new adaptive M-estimator with an asymptotically efficient score function. The adaptive M-estimator is based on using B-splines to estimate the score function and simple cross validation to determine the knots of the B-splines, which are a modified version of Kun( 1992). We herein extend this method to right-censored data and study how well the adaptive M-estimator performs for various error distributions and censoring rates. Some impressive simulation results are shown.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.555-556
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• 2020

본 논문에서는 지속적으로 증가하는 이동통신 가입자를 수용하고 초고속 모바일 데이터 서비스를 제공하기 위해서 무선 자원을 효율적으로 사용하기 위한 호 제어 방법을 제안한다. 제안된 방법에서는 핸드오버 호 요구를 효율적으로 처리하고 서비스 품질을 개선하기 위하여 핸드오버 지속시간(핸드오버 요구부터 기존 채널 절단까지의 핸드오버 영역에 머무르는 시간)을 고려하여 핸드오버 영역을 먼저 벗어나는 순서를 예측하고 이를 기준으로 우선순위가 높은 핸드오버 호를 먼저 처리한다. 제안된 방법의 성능을 분석하기 위하여 시뮬레이션을 수행하였으며, 가입자의 새로운 호의 발생 시간 간격과 호의 통화시간을 지수분포로 가정하고 지수분포의 memoryless property 특성을 이용하였다. 수행 결과, 제안된 방법이 기존의 FIFO(First-In-First-Out) 방법에 비하여 호의 블록킹 확률과 강제 종료 확률이 감소(평균 25.2%)됨을 알 수 있다.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.2
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• pp.112-121
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• 1994

This paper discusses the feasibility of ultrasonic C-scan technique for nondestructive evaluation of spot weld quality. Ultrasonic evaluation for spot weld quality was performed by immersion method with the mechanical and the electronic scanning of point-focussed ultrasonic beam(25 MHz). For the sake of the approach to the quantitative measurement of nugget diameter and the discrimination of the corona bond from nugget, preliminary infinitesimal gap experiment by newton ring is tried in order to set up the optimum ultrasonic test condition. Ultrasonic image data obtained were confirmed and compared by optical microscope and SAM(Scanning Acoustic Microscope) observation of the spot-weld cross section. The results show that the nugget diameter can be measured with the accuracy of 1.0mm, and voids included in nugget can be detected to $10{\mu}m$ extent with simplicity and accuracy. Finally, it was found that it is necessary to make a profound study of definite discrimination of corona bond from nugget and the approach of quantitative evaluation of nugget diameter by utilizing the various image processing techniques.

• Korean Journal of Food Science and Technology
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• v.52 no.4
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• pp.357-362
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• 2020

This study was conducted to investigate the effects of mushroom composition (0, 4, 8, and 12%) on the quality characteristics of an extruded meat analog. The meat analog blend was isolated soy protein, wheat gluten, and corn starch (50:40:10). The extrusion condition was set to 55% feed moisture, 170℃ barrel temperature, and 150 screw speed by high moisture extrusion using a twin-screw extruder equipped with a cooling die. The integrity index, hardness, cohesiveness, springiness, chewiness, and cutting strength of the meat analog increased with the increasing mushroom content, while its water holding capacity and nitrogen solubility index (NSI) decreased. The protein digestibility decreased with the increasing mushroom content, while the DPPH radical scavenging activity significantly increased. In conclusion, the incorporation of mushrooms into the investigated meat analog enhanced its texture and antioxidant level.

• Korean journal of food and cookery science
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• v.18 no.2
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• pp.206-210
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• 2002

The bread qualities were analyzed objectively by using CrumbScan software. Samples were prepared at the same conditions of mixing, fermentation, and baking time except the amount of Korean wheat flour (KWF). The bread volume was increased with increasing KWF, and the maximum volume was attained in the product of 20% KWF. Although the products of 20% and 30% KWF showed the same thickness of the crust, the crust was thinner than control when KWF was added. The size (fineness) and shape (elongation) of crumb cells were larger and rounder than control due to the low degree of elasticity of the KWF-added dough. Among the samples, the product with 20% KWF showed the most even distribution of crumb cells around the sliced area. The precise determination of external and internal characteristics of the bread was possible with Crumbscan, suggesting the possibility of developing industrial standards for bread.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.278-282
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• 1998

Peeled garlic, soybean sprouts, cut onion and cut green pepper were treated by dipping in solutions of different antibrowning agents, and then stored at $10^{\circ}C$. Surface color and polyphenol oxidase activity of produce were measured through the storage. Tested antibrowning agents include ascorbic acid, citric acid and allyl isothiocyanate. The commodities showed different responses to the antibrowning agent solutions; 1% citric acid for peeled garlic, 1% ascorbic acid for soybean sprouts, 2% citric acid for cut onion, and 1% ascorbic acid for cut green pepper showed better retardation in browning than the other treatments for respective product. For peeled garlic, surface browning was concomitant with increase in polyphenol oxidase activity during storage. On the other hand, there was no positive correlation between surface browning and polyphenol oxidase activity for the other stored products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1716-1729
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• 2010

In this paper, we deal with a hierarchical ring-mesh optical network design problem. The objective is to minimize the total cost of optical add-drop multiplexers (OADMs) handling intra-ring traffic, optical cross-connects (OXCs) handling inter-ring traffic, and cabling cost among OADMs and among OXCs, while satisfying intra-ring and inter-ring capacities. We develop an integer programming (IP) formulation for the problem and devise some cutting planes that partially break the symmetry of rings. Dealing with the inherent computational complexity of the problem, we devise an effective heuristic procedure that finds a good quality feasible solution within reasonable computing times. Computational results demonstrate the efficacy of the proposed solution procedure; the developed symmetry breaking inequalities significantly reduce the computing time to find an optimal solution for small size problems, and the heuristic procedure finds a better feasible solution than that CPLEX, a commercial optimization software, finds for large size problems.

• Food Science and Preservation
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• v.19 no.3
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• pp.323-327
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• 2012

The effects of ultrasound and ascorbic acid cotreatment on the browning inhibition and microbial growth of fresh-cut Tsugaru apples were investigated. The prepared samples were dipped in distilled water (Cont) or 1% (w/v) ascorbic acid solution (AA) and were then ultrasonicated in distilled water (US) or 1% (w/v) ascorbic acid solution (AA+US). The samples were then packed in a 0.04mm polypropylene bag ($20{\times}15$ cm) and were stored at $10^{\circ}C$ for eight days. The AA+US treated samples showed high $L^*$ and low $a^*$, $b^*$ values as well as inactivated PPO activity. The growth of the total aerobic bacteria also inhibited the AA+US treated samples more. The physicochemical properties were not different among all the samples. It was demonstrated in this paper that the ultrasonication treatment with ascorbic acid prevented the enzymatic browning of and microbial growth in fresh-cut Tsugaru apples.

• Air Cleaning Technology
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• v.22 no.2
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• pp.31-39
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• 2009

최근 식생활의 다양화와 식품 안전에 대한 관심 증가에 따라 식품 공장의 청정화와 작업장의 위생 관리에 대한 노력이 많이 이루어지고 있다. 그 중에 서도 농식품 분야에서는 최근 들어서 신선한 과일과 채소류를 식품소재로 이용한 신선편이 가공 농산물의 수요가 늘어나고 있다. IFPA(The International Fresh-cut Produce Association)의 정의에 따르면 신선편이 농식품은 박피되거나 절단되어져 신선함을 유지한 채로 소비자들에게 높은 영양과 편이성 및 풍미를 제공하는 포장형태의 100% 이용 가능한 과일 및 채소제품을 말한다. 이러한 신선편이 농식품은 식재료공급에 있어 안전성 및 편이성이 있으나 수확 후 처리시설에 대한 위생 개념이 도입되지 않고는 양질의 식재료를 공급하는 것은 어렵다. 그러나 신선편이 농식품은 살아있는 생체 조직으로 박피, 절단 등의 과정을 거치면서 세포가 파괴되어 급격한 품질 변화가 나타 날 수 있으며, 최소한의 비가열 가공공정만을 거치게 되므로 식품원료 내에 존재하는 미생물이 그대로 유지 될 수 밖에 없는 문제점을 가지고 있다. 또한 일반적으로 선선편이 제품의 가공과정에서 절단 처리시 표면에 묻어 있던 미생물이 과육 부위로 옮겨지면서 식품 세포 조직의 체액을 영양성분으로 활용하여 급격히 증식함으로서 식품의 변질을 일으키거나 섭취시 질병을 일으킬 수 있는 가능성이 있다. 특히, 신선편이 농식품 중에서 가장 많이 소비되는 엽채류는 수확 직후 잎 표면에 토양과 물에 의한 다양한 미생불이 부착되어 식품의 변질 가능성이 크다. 그러므로 농산물의 유통 및 보관단계에서 미생물 오염 가능성이 있기 때문에 신선편이 농식품은 원료 구입 후 제품 생산 및 포장에 이르는 과정에서 각 작업 단계별 위해요소를 분석하고, 식품 안전성을 확보하여 철저한 위생 관리가 중요하다. 따라서 본 자료는 농식품 작업장중 세척공정을 거치는 신선편이농산물과 세척공정을 거치지 않는 신선농식품 작업장에 대한 위생관리 및 관련 설비 기술 개발을 위한 기초 자료로 활용하고자 현재 운영중인 작업장을 중심으로 직접 현지 조사한 자료이다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.72-79
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• 2021

A circular saw is an effective tool for cutting glass and carbon-fiber hybrid composites. This study investigated tool wear and cut quality when reusing saw blades. The carbide saws wear four times faster than the new ones, and polycrystalline diamond (PCD) is very resistant to tool wear, except at the end of its lifespan. The cut cross-section quality is affected by the blade type, tool wear, and spindle speed. Alternate top bevel (ATB)-type blades are suitable for cutting fiber-reinforced plastics, but triple-chip grind (TCG)-type blades are unsuitable because they cause fiber-pullout defects. Tool wear and low spindle speeds increase the occurrence of arc scratches, due to the rear saw blade. A microscopic examination showed that the burr, which is a mixture of fiber chips and epoxy matrix, was bonded on top, and glass-fiber delamination occurred on the bottom glass-fiber-reinforced polymer (GFRP) surface.