• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.871-885
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• 2015

The improved DFSA for 2.4GHz multi-tags active RFID is suggested in 2 different ways: 1) simplified tag collection and Ack procedure using query command and 2) modified Schoute's method to control the number of slots in the frame. To evaluate the performance of the improved system we develop the simulation model. Varying the number of tags in the system we track the performance measures such as throughput, recognition time for multi-tags and tag recognition rate during a given time. The suggested method shows the best performance over all measures. Simplification of collection and Ack commands using query commands contributes to reducing tag recognition time. And the modified Schoute's method which controls the frame size using $k_1$ and $k_2$ contributes to throughput improvement and reduces target cognition time by reducing the number of collection rounds.

• Journal of Technologic Dentistry
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• v.35 no.4
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• pp.295-302
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• 2013

Purpose: The grindability of Ti-10%Zr-X%Cr(X=0,1,3) alloys in order to develop Ti alloys for dental applications with better machinability than unalloyed titanium has been evaluated. Methods: Experimental Ti-10%Zr-X%Cr(X=0,1,3) alloys were made in an argon-arc melting furnace. Slabs of experimental alloys were ground using a SiC abrasive wheel on an electric handpiece at one of the four rotational speeds of the wheel (12000, 18000, 25000 or 30000rpm) by applying a force(100gf). Grindability was evaluated by measuring the amount of metal volume removed per minute(grinding rate) and the volume ratio of metal removed compared to the wheel material lost, which was calculated from the diameter loss (grinding ratio). Experimental datas were compared the results with those of cp-Ti(commercially pure titanium) Results: It was observed that the grindability of Ti-10%Zr-X%Cr(X=0,1,3) alloys increased with an increase in the Cr concentration. More, they are higher than cp-Ti, particularly the Ti-10%Zr-3%Cr alloy exhibited the highest grindability at all rotational speeds except 12000rpm. There was significant difference in the grinding rate and grinding ratio between Ti-10%Zr-3%Cr alloy and cp-Ti at all rotational speeds(p<0.05). Conclusion: The Ti-10%Zr-3%Cr alloy exhibited better grindability at high rotational speeds, great potential for use as a dental machining alloy.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.4
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• pp.22-29
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• 2015

Many enterprises have been adopting management systems good enough for them and operating the schemes to have competitive edge better than their competitor. One of the finest systems that most companies have been selecting is ISO 14001. ISO 14001, environment management system, is widely known as advancing internal efficiency and productivity in the various industries. As a result, the number of companies that have adopted ISO 14001's certification have been increasing continuously year by year since ISO 14000 standard was called in 1994s from ISO 18000 standard that originally used. The purpose of this study is to present that ISO 14001's requirement execution influences on management performance in the small manufacturer. In order to carry out this research, we obtained 96 survey sheets and inspected ten assumptions based on the reliability, validity of the questionnaires. The results of regression analysis are summarized as follows; First, the three factors of ISO 14001 requirement, plan, implementation and operation and management consideration, have an important effect on the operational performance. Second, the three elements of ISO 14001 requirement, environment policy, implementation and operation and management consideration, affect to the financial performance significantly. Based on the results, it is sure that the companies that execute the factors of implementation and operation and management policy have a good performance to achieve operational and financial performance so that it is important to clarify the member's role, authority and follow the procedure by a company's process. Also, the truth shows CEO's continuous will and periodical review of ISO 14001 influence on management performance as well.

• Korean Journal of Plant Resources
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• v.8 no.2
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• pp.183-188
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• 1995

This experiment was carried out to clarity the effect of summer softening cultivation on bud yield of Aralia continentalis Kita. Bulbous plant harvested on March 25 and stored in low temperature storage room($0-2^{\circ}C$) were transplanted in May, June, July and August. The bulbous plants were grown under black PE film and 50%(T-2250) silver shading nets. The results obtained are summerized as fallows. Harvesting time in Jul. and Aug. transplanting was 15days and was speeling 5days in May transplanting. The accumulative temperature of whole growth period was about $400^{\circ}C$. But yield of soft stems in June transplanting was 6.64(ton/ha), which was more than others. High temperature induced low-quality of soft stem in transplanting in July. Net income was 18000(1000won/ha) in transplanting in May or June.