최근 전자태그(RFID : Radio Frequency Identification)를 부착하여 비접촉식으로 다 양한 물품의 정보를 받아 물품의 추적 및 정보확인이 가능한 RFID 시스템을 작업현장에 도입/확산시키고자하는 연구들이 진행되어지고 있다. RFID 시스템은 무선인터페이스 환경에서 태그는 안테나에 정보를 담은 주파수를 보내고 있으며, 이 환경에서의 작업자는 주파수에 노출되어있다. 따라서 작업자 주파수에 노출되는 RFID 시스템 환경 에서 주파수가 작업자에게 미치는 영향에 대한 안전성평가가 필요하다.

In this study has investigated and considered product planning methods at the existing product design process and being used the safety evaluation methods at the product planning stage, and has deduced the 16 safety evaluation elements to have to be considered for executing the safety evaluation at the product planning stage. When the safety evaluation is executed from the product planning stage, more safe products will be designed.

Recently, there is a rise of accident by some defective products, especially it reported that a serious fact is a defect of design causing some problem since execute a product liability(PL), people who use products have been able to bo remunerated for a damage to those defects, so responsibilities of companies are rising more and more. Therefore, companies that are obligated to manufacture a safety product, and should make preparation for PL. For solving the problem, even though manufacturers tried to make a safety product ay mixed ways, it is seldom that its safety is considered from planning a design. This thesis has suggested a way aimed at improving a safety of products through considering a stage of a plan, by searching and analyzing the design-process in to each steps.

For the development of acoustic fishing method, the noises of fishes have been recorded and analy/'ed by many scientists. Some specimens of fishes were selected as such Cyprinus carpio, Ctenopharyngodon idellus Carassius carassius, and pagrosol1ms major in this experiment. The noises such as feeding noise, driving away noise, jumping noise and fi llip noise were recorded by the tape recorder, Sony Model 262, through the underwa te r microph I one, Oki ST 6582, and analyzed in frequencies bv octave band analyzer, Rion SA-55, and sound pressure level of source by sound level meter, Rion NA-opNN The supplied feed was placed within 5em apart from the hydrophone. The result of analyzed noises were as follow. Cyprinus carjJio; Feeding noise 250- 500 cps, 92- 99 dB Driving away noise 125-2, 000 eps, 101-112 dB Jumping noise 125-2, 000 eps, 99-116.5 dB Ctenopharyngodon idcllus; Driving away noise 125-1, 000 cps, 96-109 dB Carassius carassius; Feeding noise 250- 500 cps, 91. 5- 99.5 dB Driving away noise 125-1, 000 eps, 99-108 dB Carassius auratus Feeding noise 250 eps, 94-101 dB Driving away noise 125-1, 000 cps, 98-110 dB Pagrosomus major Feeding noise 230-500 cps, 90-101 dB Fillip noise 500 cps, 98-108 dB (1) Feeding noise was produced as like as snap noise of twig and gulping down saliva noise in human and dominant frequency range of the noise is 250-500 cps and noise level 90-101 dB. (2) It was found that feeding noise were not a monotonic but a complex tones though fish took the same food. (3) Driving away noise was produced not so keen and the wave form of the noise is rising very sharp and big amplitude in the oscillograph. Dominant frequency range of this noise was about 150-1, 000 cps and noise level 96-112 dB except thut of carp. (4) The frequency of snapper's fillip noise, when it produced by caudal fin in swimming at the surface of water, was 500 cps and noise level 93-108 dB snd that of jumping noise of carp about 150-2, 000 cps and noise level 99-116.5 dB.

Background: Cylindrocarpon destructans (Zins) Scholten is an important pathogenic fungus that causes ginseng root rot in many ginseng growing areas in China. Although C. destructans have been studied worldwide, research on its chemotaxis towards ginseng (Panax ginseng C. A. Meyer) root exudates in the rhizosphere remains limited.Methods and Results: In this study, we collected ginseng root exudates with three different polarities from three-year-old ginseng roots, and performed chemotaxis and spore germination assays to investigate the ability of these exudates to induce the response in C. destructans. The results showed that, compared with other conditions, when C. destructans cultivated at 20°C and a pH of 6 exhibited a strong positive chemotactic response toward 2 ㎎/ℓ aqueous phase, 20 ㎎/ℓ butanol phase, and 0.2 ㎎/ℓ petroleum ether from ginseng root exudates, the chemotactic moving indexes were 0.1581, 0.1638 and 0.1441, respectively. In addition, the spore germination rate with optimal chemotactic parameters were 48%, 53%, and 41% in the aqueous phase, butanol phase and petroleum ether groups, respectiviely, which were significantly higher than that in the control group (23%) (p < 0.05). The mycelial growth rate with optimal chemotactic parameters increased with culture time, and the maximum growth rates in the aqueous phase, butanol phase and petroleum ether groups were 0.425, 0.406 and 0.364 respectively, on the 4th day. The optimal chemotactic parameters were 39.73 ㎎/50 ㎎/ℓ , 48.93 ㎎/50 ㎎/ℓ , and 31.43 ㎎/50 ㎎/ℓ , in aqueous phase, butanol phase and petroleum ether respectively, from ginseng root exudates, compared with 5.5 ㎎/50 ㎎/ℓ , in the control group.Conclusions: The present study revealed that certain ginseng root exudates containing chemical attractants act as nutritional sources or signals for C. destructans and support its colonization of ginseng roots.