• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.208-208
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• 2007

• School Mathematics
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• v.16 no.3
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• pp.445-469
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• 2014

This study aims to examine secondary mathematics teachers' understanding of the levels of cognitive demand on mathematical tasks suggested in mathematics textbooks. The study also attempts to investigate whether the teachers are able to characterize the tasks accordingly and to change low level tasks to high level ones. For this purpose, we developed a survey and 50 secondary mathematics teachers participated in the survey. The findings from the data analysis suggest that 59 percent of the teachers selected high level tasks as appropriate for achieving the national curricular goals, but about 1/3 of the teachers identified PNC tasks as high level ones. The results also reveal that more than half of the teachers were not able to transform low level into high level tasks and only 4 teachers out of 50 were able to transform successfully. The teachers seem to find difficulty in transforming low level tasks into high level ones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8A
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• pp.656-663
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• 2005

This paper presents a multi-channel enhancement scheme for the MAC protocol of IEEE 802.15.3 High-rate WPAN (Wireless Personal Area Network). The current MAC protocol of the IEEE 802.15.3 High-rate WPAN is designed for sharing a single channel among DEVs of a piconet; that is, within a single piconet, PNC prevents interference through MAC layer assignment of time slots to other DEVs using time-division multiple access. When the number of DEVs that communicate with each other frequently, is increased in a single WPAN, the size of the superframe becomes inevitably large, and this may result in a significant throughput drop or a failure to provide QoS guarantee. A multi-channel enhancement scheme for the MAC protocol of IEEE 802.15.3 High-rate WPAN is proposed to significantly increase the aguegate throughput and more reliably provide the QoS guarantees in a piconet

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3A
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• pp.230-236
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• 2007

This paper presents a resource management mechanism for the mesh networking in IEEE 802.15.3 High-rate WPAN. IEEE 802.15 TGS is standardizing the MAC and PHY for mese networking. This task group researches the mechanism that are extension of network coverage without increasing transmit power of receive sensitivity, and studies the enhanced reliability via route redundancy. In this paper we propose the distributed resource management scheme that is fairly using the channel resource in the piconet without centralized piconet coordinator. Each DEV reserves the channel time and broadcasts its information. This scheme has unfairness for later associated DEV because of preoccupation of earlier associated DEVs. This paper presents the method that fairly allocates the channel time in MAC layer. And we evaluate the performance enhancement using simple simulations.

• Journal of Korea Port Economic Association
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• v.28 no.2
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• pp.179-194
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• 2012

In this study, we compared the efficiency of container terminals using DEA. To do this, we designed an AHP/DEA hybrid model using AHP and DEA, and evaluated the efficiency by comparing the container terminal operation company in Gwangyang(KEC, KIT, GICT) and Busan(HBCT, DPCT, KBCT, UPT, Gamman, PNC, PNIT, HJNC, HPNT). The proposed model can control the number of selected promising container terminal by applying DEA-AR model. This model can also improve the credibility of analysis by using objective weights through the AHP application to efficiency evaluation data and normalizing the evaluation data to apply AHP and DEA. The model assumes inputs to be container crane, transfer crane, yard tractor, and reach stacker and output as container traffic. The result shows that DPCT was an efficient DMU.

• Korean Journal of Veterinary Service
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• v.30 no.3
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• pp.393-406
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• 2007

Bovine tuberculosis is an important zoonosis worldwide. Mycobacterium bovis, the causative agent of this disease in cattle, is also a pathogen for humans and several economically important animals. The cases of tuberculosis are reported in two cow found at slaughter house located in Gwangju city. Histopathologically, in the lymph nodes, granulomas consisted of large areas of necrosis surrounded by variable thick bands of cellular infiltrate containing macrophages, Langhans-type multinucleated giant cells and lymphocytes. Lesions in the lung followed the same developmental pattern as did lesions in the lymph nodes with some exceptions. With the acid-fast staining, numerous mycobacteria were revealed in the lung and lymph nodes. M bovis was confirmed as a causative agent in these cattle using bacterial isolation and PCR and restriction fragment length polymorphism method based on a unique 12.7 kb fragment insertion sequence from the Mycobacterium tuberculosis genome and the pncA polymorphism, The insertion element IS6110 and IS1081 were present M bovis isolated from lungs and lymph nodes of cattle using PCR assay. These cases are interesting and important in public health aspect that M bovis-infected cattle were found during a routine post-mortem inspection at slaughter house.

• The Mathematical Education
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• v.60 no.1
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• pp.61-76
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• 2021

The purpose of this study is to analyze the errors and difficulties which pre-service secondary teachers shows during the task modification in consideration of the cognitive demand and to provide significant implications to the pre-service teacher education program related to the modification of the mathematical tasks. In the pursuit of this purpose, tasks were selected from perpendicular bisector units and 24 pre-service teachers were asked to modify the tasks to higher and lower level tasks. After the modification activities, opportunities for reflection and modification were provided. The findings from analysis are as follows. Pre-service teachers had a difficulty to distinguish between PNC tasks and PWC tasks. Also, We identified the interference phenomena that pre-service teachers depended on the apparent elements of the task. Pre-service teachers showed a tendency to overlook the learning objectives and learning hierarchy during the task modification, and to focus on some types of task modification. However, pre-service teachers were able to have meaningful learning opportunities and extend the category of tools to technology including Geogebra through self-reflection and correction activities on task modification. The above results were summed up and we presented the implications to the task modification program in the pre-service secondary teacher education.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.239-246
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• 2021

The fertility of dairy cows has been declining worldwide. The number of services per conception has increased, and repeat breeder (RB) cows are considered important in the dairy industry. However, there has been little research on RB cows in Korea. The objective of this study was to investigate the relationship between serum biochemical profiles and RB Holstein cattle in Korea and compare the results with those of studies conducted abroad. In addition, we investigated hidden factors that are needed for RB cattle to become pregnant. Overall, 34 Korean Holstein Friesian cows were divided into three groups: pregnant with normal cycling (PNC), pregnant with repeat breeder (PRB), and non-pregnant with repeat breeder (NRB). Blood samples were collected from the jugular vein, and serum parameters (ALT, AST, ALP, GGT, LD, CK, TP, ALB, GLOB, TBIL, BUN, CRE, GLU, TC, TG, NEFA, CA, MG, and IP) were analyzed. GGT levels were significantly different among groups (P=0.01). The concentration of GGT was the highest in the NRB and the lowest in the PNC. In contrast to the findings of other studies, there were no differences in GLU, TP, TC, and BUN levels. This study is the first to investigate serum biochemistry in RB cattle and provides results that differ from those of previous studies; these findings would help establish a novel approach to improve fertility of RB cattle.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.505-507
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• 2003

IEEE 802.15.3 High­Rate WPAN(Wireless Personal Area Network)는 10m 내외의 무선환경에서 실시간 비디오, 고품질 오디오 및 대용량 파일 전송을 가능케 하는 기술이다. 하나의 네트워크를 piconet단위로 구성하고 하나의 piconet에는 PNC(piconet coordinator)가 TDMA(Time Division Multiple Access) 방식으로 DEV(device)들에게 채널타임을 할당한다. 본 논문에서는 IEEE 802.15.3 High­Rate WPAN 환경에서 하나의 piconet이 형성된 경우 동시에 여러 개의 채널을 최대한 활용하기 위한 다중 채널 MAC을 제안하고 이를 위한 타임 할당 방식을 연구한다.

• Journal of Pharmaceutical Investigation
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• v.6 no.3
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• pp.4-9
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• 1976

Free amino acids in water extracts and total amino acids in hydrolystates of Deer Horn were analyzed by amino acid autoanalyzer (Technicon PNC-1 Type). The results obtained from this study are as follows ; 1) 17 kinds of amino acid, including 7 kinds of essential amino acid in human nutrition except tryptophan were identified and quantified. 2) Of all free amino acid contained in water extract, glutamic acid is the richest, and then comes Ala, Gly, Leu, Lys, valin in that order. Of all total amino acid which are closely related with nutritional valuation glycin is the richest, and then comes Glu, Lys, Ala, Leu, Ala, Pro, in that order. 3) Besides 17 kinds of amino acid, one kinds of unknown amino acid are found in water extracts and hydrolysates.