• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1A
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• pp.1-6
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• 2003

We propose a mathematical model to analyze the performance of TD-CDMA/TDD systems in terms of call blocking probability and then find the optimum time-slot switching-point at the smallest call blocking probability considering asymmetrical traffic load distribution for various kinds of service applications.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.715-717
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• 2001

기존의 강성 실시간 시스템은 실시간 수행만 고려되어 있어. 실시간 시스템의 성능과 효율적인 시스템 활용과는 거리가 멀다. 따라서 효율적인 시스템 활용을 통하여 보다 많은 일을 수행할 수 있게 하는 연성 실시간 시스템을 사용하게 된다. 여기서는 보상값이라는 것을 사용하여 그것의 총합을 성능평가의 기준으로 사용하며, 보상값의 합을 최대로 할 수 있는 수행시간을 찾아 스케줄링에 사용하게끔 한다. 모의 실험을 통하여 알아낸 수행시간에 따른 보상값의 변화에 대한 경향을 이용하여 최대 보상값을 얻을 수 있는 수행시간을 찾고, 실험을 통하여 얻은 결과와 비교하였다.

• Journal of the Korea Society of Computer and Information
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• v.21 no.2
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• pp.97-103
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• 2016

This paper deals with the cycle time minimization problem that determines the productivity in printed circuit board (PCB) with n components using the m placement machines. This is known as production cycle time determination problem (PCTDP). The polynomial time algorithm to be obtain the optimal solution has been unknown yet, therefore this hard problem classified by NP-complete. This paper gets the initial assignment result with the machine has minimum unit placement time per each component firstly. Then, the balancing process with reallocation from overhead machine to underhead machine. Finally, we perform the swap optimization and get the optimal solution of cycle time $T^*$ within O(mn) computational complexity. For experimental data, the proposed algorithm can be obtain the same result as integer programming+branch-and-bound (IP+B&B) and B&B.

• Journal of Food Hygiene and Safety
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• v.37 no.3
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• pp.173-180
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• 2022

There are a number of methods to evaluate the quality of squid. However, when purchasing the fish, consumers and retails rely only on the sensory test and flavor in the field. Therefore, this study was aimed to prove relationship between scientific indicator and sensory test. Total viable cell count (TVC), viable cell count of Pseudomonas spp., pH and volatile basic nitrogen (VBN) were selected as scientific indicators and mesured during the storage of squid at different temperature. The squid was storaged at 3 different temperature (5℃, 15℃, 20℃). Off flavor determination time was measured by R-index, and kinetic modeling was conducted. Activation energies of off-flavor determination time, TVC, Pseudomonas spp, VBN, and pH were 51.210 kJ/mol, 42.88 kJ/mol, 50.283 kJ/mol, 72.594 kJ/mol and 41.99 kJ/mol respectively. Activation energy of off-flavor determination time was approximated to viable cell count of Pseudomonas spp., TVC, pH and VBN as an order. Especially, viable cell count of Pseudomonas spp. had best match of the activation energy. Therefore, it was judged that indicator of off-flavor determine time was viable cell count of Pseudomonas spp..

• Food Science and Biotechnology
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• v.14 no.4
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• pp.466-469
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• 2005

Chinese cabbage (Brassica campestris L. Pekinensis) is Brassica vegetable that contains high amounts of glucosinolates. Glucosinolates and their breakdown products are thought to contribute to health promotion by preventing some cancers. Chinese cabbage is the most commonly consumed vegetable in Asian countries including Korea. In this study, qualitative and quantitative analyses of 3-butenyl glucosinolate (Gluconapin) from different cultivars and different parts of the cabbage were performed. Gluconapin of Chinese cabbage was extracted by hot ethanol ($80^{\circ}C$), isolated by an anion exchange column and identified by GC/MS and LC/MS. The levels of glucosinolates in Chinese cabbage varied according to the different parts, cultivars, and blanching time. In general, the concentrations of 3-butenyl isothiocyanate (ITC) were higher in the leaf than in the midribs parts. The cultivar 'Bulam no. 3' had a much greater content of 3-butenyl ITC than the cultivar 'Garak no. 1,' and the levels of butenyl ITC were highest after two weeks of storage. Blanching treatment decreased the concentration of 3-butenyl ITC. The ITC concentration varied extensively among different crops of the same species, and according to the different parts on the cabbage, the storage duration and the boiling time.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.502-507
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• 2003

Toward the development of practical methods for observed data oriented bispectral estimation, an automatic means for determining the smoothing bandwidth of bispectral windows is proposed, that can also provide an associated optimum bispectral estimate of stationary non-Gaussian signals, systematically only from an observed time series datum of finite length. For the conventional non-parametric bispectral estimation, the MSE (mean squared error) of the normalized estimate is reviewed under a certain mixing condition and sufficient data length, mainly from the viewpoint of the inverse relation between its bias and variance with respect to the smoothing bandwidth. Based on the fundamental relation, a systematic method not only for determining the bandwidth, but also for obtaining the optimum bispectral estimate is presented by newly introducing a MSE evaluation index of the estimate only from an observed time series datum of finite length. The effectiveness and fundamental features of the proposed method are illustrated by the basic results of numerical experiments.

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.649-656
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• 2006

The proposed head-space supercritical fluid extraction (SFE) methodology as an alternative to an existing conventional procedure was explored for the determination of organochlorine compounds in aqueous matrix. In this study, polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were utilized as target analytes. To enhance the recovery efficiency, the factors such as the $CO _2$ density, the extraction time, and the extraction mode were investigated. Furthermore, the analytical procedures and the results obtained were compared with those provided by the conventional method (the U.S. EPA method 8080). Under the optimized conditions, i.e., a combination of static with dynamic SFE mode at 2,000 psi and 40 ${^{\circ}C}$, the head-space SFE methodology gave equivalent or better to the conventional method in recovery efficiencies with clear advantages such as simple sample treatment and fast analysis time as well as reduced solvent and reagent consumption.

• Carbon letters
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• v.26
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• pp.43-50
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• 2018

In this research, a novel and efficient quinoline thioacetamide functionalized magnetic graphene oxide composite ($GO@Fe_3O_4@QTA$) was synthesized and utilized for dispersive magnetic solid phase preconcentration of Cd(II) and Ni(II) ions in urine and various food samples. A number of diverse methods were employed for characterization of the new nanosorbent. The design of experiments approach and response surface methodology were applied to monitor and find the parameters that affect the extraction performance. After sorption and elution steps, the concentrations of target analytes were measured by employing FAAS. The highest extraction performance was achieved under the following experimental conditions: pH, 5.8; sorption time, 6.0 min; $GO@Fe_3O_4@QTA$ amount, 17 mg; 2.4 mL $1.1mol\;L^{-l}$ $HNO_3$ solution as the eluent and elution time, 13.0 min. The detection limit is 0.02 and $0.2ng\;mL^{-1}$ for Cd(II), and Ni(II) ions, respectively. The accuracy of the new method was investigated by analyzing two certified reference materials (sea food mix, Seronorm LOT NO 2525 urine powder). The interfering study revealed that there are no interferences from commonly occurring ions on the extractability of target ions. Finally, the new method was satisfactorily employed for rapid extraction and determination of target ions in urine and various food samples.

• Analytical Science and Technology
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• v.6 no.3
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• pp.313-318
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• 1993

The rose petal tissue biosensor has been constructed by immobilizing New carina rose tissue. Optimum conditions for the determination of urea were investigated using this sensor. Selectivity and life time of this sensor were also obtained. As a result, the biosensor showed the optimum response characteristics in 0.20M phosphate buffer solution at pH 8.0, $37^{\circ}C$ and 50mg of tissue amounts. This sensor was linear from $9.0{\times}10^{-5}$ to $4.0{\times}10^{-3}M$ urea with a slope of 42mV/decade. The limit of detection and response time are $7.0{\times}10^{-5}M$ and 17~19 min.

• Journal of Embryo Transfer
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• v.30 no.4
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• pp.335-340
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• 2015

The objective of this study was to evaluate the initial detection time and development of the fetal genital structures using ultrasound in twelve pregnant small bitches. The initial detection time of the fetal genital structures was as follows: genital tubercle at days 32.6; os penis at days 45.2; labia at days 45.7; scrotum at days 47.5. Ultrasonograms of fetal genital structure according to gestational stage were as follows: Undifferentiated stage (before day 35), the genital tubercle was observed to have a small elevation and just a hyper-echogenic structure in the midline between the umbilical cord and the tail in male and female fetus. Migration stage (between day 35~45), the genital tubercle was observed as a hyper-echogenic, bilobular, oval shaped and the genital tubercle began to migrate from the initial position toward the umbilical cord in males, and toward the tail in females. Differentiated stage (after day 46), the penis and os penis were observed to stand out in the abdominal wall and the scrotum was observed toward the perineal region in male fetuses. The labia was detected at the base of the tail in female fetuses. These results indicate that ultrasound of fetal genital structures could be useful for fetal gender determination and a completely prepartum evaluation of the canine fetus.