Microbial parameters of indoor air containing systematic, random, and accidental error were analyzed statistically by the water quality control guidelines to suggest a guideline of indoor air. Samples were collected from 20 subway stations of Seoul Metropolitan City. Systematic errors resulted from sampling devices were checked and removed by using same devices and flow rate check. Another source of systematic error resulted from different testing personals were assessed and qualified by proficiency test. Increase of replicate sample numbers could minimize random errors and use of geometric mean instead of arithmetic mean gave more statically reliable representative values for microbial parameters. Considerations for the culture media, colony counting results with incubation time, and statement of supplemented statistical data were also suggested.

생물학적 자극통제 수단으로서 활용하기 위한 새로운 돼지 웅성 페르몬성 물질을 탐색하고자 lipocalin의 수용체인 돼지 웅성 페르몬 P1과 P2의 리간드에 기초하여 54개의 P1 및 P2 유사체들에 대한 분자 유사성 지수 (S)는 물론, 분자량 (MWt), 소수성 (logP), 몰라 굴절율 (MR), van der Waals 분자 표면적 (SA), van der Waals 분자 부피 (MV), HOMO, LUMO 에너지, 이온화 포텐셜 (IP), 생성열 (HF), 리폴(lipole), 쌍극자 능율 (DM) 및 전체 에너지 (TE)등, 다양한 13종의 물리-화학 파라미터들을 계산하고 비교 검토하였다. 이들 스테로이드 유사체들의 물리-화학적인 성질은 주로 A와 D-고리가 입체적으로 상이함에 따라 의존적이었며 또한, S와 MV 상수와의 상관관계로부터 분자들의 MV상수가 작아질수록 S=1에 근접하는 경향이었다. 이같은 결과에 근거하여 P1-1과 P2-1 등, 2개의 화합물이 유사성 지수뿐 만 아니라, 소수성, 몰라 굴절율 및 분자부피 등의 측면에서 기존의 페르몬성 물질과 유사한 경향을 보이므로 새로운 돼지 웅성 페로몬성 화합물로 예상되었다.

An electric motor is the one of the most important parts in robot systems, which mainly drives the wheel of mobile robots or the joint of manipulators. According to the requirement of motor performance, the controller type and parameters vary. For the wheel driving motors, a speed tracking controller is used, while a position tracking controller is required for the joint driving motors. Moreover, if the mechanical parameters are changed or a different motor is used, we might have to tune again the controller parameters. However, for the beginners who are not familiar about the controller design, it is hard to design pertinently. In this paper, we develop a nominal robust controller model for the velocity tracking of wheel driving motors and the position tracking of joint driving motors based on the disturbance observer (DOB) which can reject disturbances, modeling errors, and dynamic parameter variations, and propose the methodology for the determining the least control parameters. The proposed control system enables the beginners to easily construct a controller for the newly designed robot system. The purpose of this paper is not to develop a new controller theory, but to increase the user-friendliness. Finally, simulation and experimental verification have performed through the actual wheel and joint driving motors.

Unlike many laboratory-scale studies on absorption of organic compounds (VOCs), limited pilot-scale studies have been reported. Accordingly, the present study was carried out to examine operation parameters for the effective control of a hydrophilic VOC (methyl ethyl ketone, MEK) by applying a circular pilot-scale packed-absorption system (inside diameter 37 cm × height 167 cm). The absorption efficiencies of MEK were investigated for three major operation parameters: input concentration, water flow rate, and ratio of gas flow-rate to washing water amount (water-to-gas ratio). The experimental set-up comprised of the flow control system, generation system, recirculation system, packed-absorption system, and outlet system. For three MEK input concentrations (300, 350, and 750 ppm), absorption efficiencies approached near 95% and then, decreased gradually as the operation time increased, thereby suggesting a non-steady state condition. Under these conditions, higher absorption efficiencies were shown for lower input concentration conditions, which were consistent with those of laboratory-scale studies. However, a steady state condition occurred for two input concentration conditions (100 and 200 ppm), and the difference in absorption efficiencies between these two conditions were insignificant. As supported by an established gas-liquid absorption theory, a higher water flow rate exhibited a greater absorption efficiency. Moreover, as same with the laboratory-scale studies, the absorption efficiencies increased as water-to-gas ratios increased. Meanwhile, regardless of water flow rates or water-to-gas ratios, as the operation time of the absorption became longer, the pH of water increased, but the elevation extent was not substantial (maximum pH difference, 1.1).