Quality requirements of manufactured products or parts are given in the form of specification limits on the quality characteristics of individual units. If a product is to meet the customer’s fitness for use criteria, it should be produced by a process which is stable or repeatable. In other words, it must be capable of operating with little variability around the target value or nominal value of the product’s quality characteristic. In order to maintain and improve product quality, we need to apply statistical process control techniques such as histogram, check sheet, Pareto chart, cause and effect diagram, or control charts. Among those techniques, the most important one is control charting. The cumulative sum (CUSUM) control charts have been used in statistical process control (SPC) in industries for monitoring process shifts and supporting online measurement. The objective of this research is to apply Taguchi's quality loss function concept to cost based CUSUM control chart design. In this study, a modified quality loss function was developed to reflect quality loss situation where general quadratic loss curve is not appropriate. This research also provided a methodology for the design of CUSUM charts using Taguchi quality loss function concept based on the minimum cost per hour criterion. The new model differs from previous models in that the model assumes that quality loss is incurred even in the incontrol period. This model was compared with other cost based CUSUM models by Wu and Goel, According to numerical sensitivity analysis, the proposed model results in longer average run length in in-control period compared to the other two models.

The aim of this study was to examine indoor fungal concentration and fungal volatile organic compounds(VOCs) in single-person households. A total of 22 houses occupied by one person were investigated in this study. 19 VOCs detected in the field were estimated as fungi-derived VOCs through a review of the literature, and 11 VOCs were confirmed as fungal VOCs by laboratory experiments. Exposure to fungal VOCs in the indoor environment has been confirmed to be highly influenced by airborne fungal concentration and indoor humidity. 3-octanone was characterized by a clear generation profile in Aspergilus versiocolor, and n-decane in Pencillum chrysogenum. ntetradecane emitted by Stachybotrys chartarum exhibited a tendency to occur consistently. The observations made in this study demonstrated that single-person households can easily be exposed to fungi, and MVOCs can be used as an indicator of fungal exposure in indoor environments.

본 연구는 실제 유류오염토양을 in situ 토양세정법으로 정화시 기술 적용성을 평가하기 위한 회분식 기초연구로 적정 계면활성제의 종류와 농도를 결정하고자 하였다. 증류수만의 진탕효과로 인한 TPH 제거는 약 30%이었으며, 계면활성제 희석시 사용되는 용액으로는 증류수를 사용한 경우에 비하여 지하수(해수 혼합)의 유입으로 인하여 약 2~6%의 효율저하가 나타났다. 토양과 계면활성제 용액비는 회분식 실험에서 TPH 제거효율에 미치는 영향이 미미하였다. 단독 또는 혼합 계면활성제 농도를 0.1~4.0 wt%까지 변화시켜 세정한 결과 종류별로는 Tween-80, SWA-1503, SWA-1503+SDS에서 평 균 제거율이 80% 이상으로 대체적으로 높은 효율을 보였으며, 농도에 따른 차이는 크지 않아 0.1 wt% 농도를 최적 농도로 판단하였다.

SrSnO3 phosphor powders were synthesized with two different contents of activator ions Eu3+ and Tb3+ using thesolid-state reaction method. The structural, morphological, and optical properties of the phosphors were investigated using X-ray diffractometry, field-emission scanning electron microscopy, and fluorescence spectrophotometry, respectively. All thephosphors showed a cubic structure, irrespective of the type and the content ratio of activator ions. For Eu3+-doped SrSnO3phosphors, the intensity of the 620nm red emission spectrum resulting from the 5D0→7F2 transition of Eu3+ was stronger thanthat of the 595nm orange emission signal due to the 5D0→7F1 transition in the range 0.01-0.05mol of Eu3+, but the ratio ofthe intensity was reversed in the range 0.10-0.20mol of Eu3+. The variation in the emission intensity indicates that the sitesymmetry of the Eu3+ ions around the host crystal was changed from non-inversion symmetry to inversion. For the Tb3+-dopedSrSnO3 phosphors under excitation at 281nm, one strong green emission band at 550nm and several weak bands wereobserved. These results suggest that the optimum red and green emission signals can be realized when the activator ion contentfor Eu3+- or Tb3+-doped SrSnO3 phosphors is 0.20mol and 0.15mol, respectively.

A field study was conducted to compare growth, feed utilization and nutrient excretions by feeding extruded pellet (EP) and moist pellet (MP). Slow growing flounder were used as the experimental animal to find out a prominent result in terms of growth and feed utilization. Weight gain of fish fed the experimental diets for 8 weeks reached 105.3 g for EP and 107.1 g for MP, while fresh feed intake was 98.7 g for EP and 279.4 g for MP. Feed conversion ratio was 0.94 and 2.61 for EP and MP, respectively which was 0.77 and 0.94 when corrected on dry matter basis. Even though protein efficiency ratio (2.26 vs 2.21), specific growth rate (0.69% vs 0.70%), daily weight gain (2.06 g vs 2.10 g) and mortality (4.0% vs 4.1%) were similar between EP and MP, protein retention efficiency of fish fed EP was superior (53.3%) to that of fish fed MP (39.6%). Protein intake of fish for 8 weeks was similar from 52.3 g for EP to 53.3 g for MP, while protein gain was higher in fish fed EP (27.9 g) than in fish fed MP (21.1 g). Protein excretion by feeding EP and MP reached 232 g and 300 g, respectively per kg gain, suggesting that protein loads could be greatly reduced in practical culture system through the use of EP. Phosphorus (P) intake was much lower in fish fed EP (1.63 g) than in fish fed MP (2.18 g), while retention of P was higher in fish fed EP (0.88 g) than in fish fed MP (0.78 g), showing the retention efficiency of 54.0% and 35.9%, respectively. Fish fed EP excreted 7.1 g of P per kg gain which was much lower than that of fish fed MP (13.1 g). The present results clearly showed that EP feeding for flounder is not only productive but also environmentally friendly.