• Journal of Korean Society of Water and Wastewater
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• v.12 no.2
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• pp.106-114
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• 1998

In this research, single-, two- and four-stage intermittently aerated activated sludge system were investigated for simultaneous removal of nitrogen and phosphorus with swine wastewater. For the comparison of removal efficiency, conventional activated sludge system was operated. Operational conditions of intermittently aerated activated sludge system were SRT 20day, HRT 24hr and aeration/nonaeration time 1hr/1hr, respectively. Nitrogen and phosphorus removal efficiency in Intermittently aerated activated sludge system was upgraded compare with conventional activated sludge system. In single-stage intermittently aerated activated sludge system, release-uptake of $PO_4^{3-}-P$ was observed very well but, phosphosrus removal in effluent was not effective. In single-stage intermittently aerated activated sludge system, release-uptake of $PO_4^{3-}-P$ in first reactor, was observed very well but, in following reactor, $PO_4^{3-}-P$ concentation showed almost no change. T-N removal efficiency in conventional activated sludge system, single-, two-, and four-stage intermittently aerated activated sludge system were 48, 87, 90.9 and 95.5%, respectively, and phosphorus removal efficiency were 48, 75, 97 and 95%, respectively. Intermittently aerated activated sludge system as a alternative processes of conventional system leads to meet satisfactory effleunt with only on/off aeration regulation and save energy for aeration.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.179-183
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• 2004

This study was conducted to investigate the effects of using barley seeder attached to rice harvest combine that could be used in rice harvesting and barley seeding simultaneously on the growth characteristics of barley and labor-saving efficiency. In developed seeding system, burley seeding was earlier about 5 days than in the conventional system, because of conducting rice Harvesting and barley seeding simultaneously. The germination of barley seed after seeding was protected from drought damage by the rice straw covering. Among the growth characteristics of barley using developed seeding system, the number of spikes per m$^2$ was lower than that of conventional system, but others showed longer culm length, hove kernel numbers per spike and heavier 1,000 kernel weight than those of conventional system. Developed seeding system resulted in about 57% labor-saving efficiency compared with conventional system. The cost of whole works from seeding to harvest of barley was saved about 8% compared with conventional system. A total of income increased about 16% than that of conventional system.

• The Korean Journal of Cytopathology
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• v.15 no.1
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• pp.33-39
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• 2004

We compared the diagnostic accuracy of liquid-based cervicovaginal cytology using $MonoPrep2^{TM}$ system (Monogen, Herndon, Virginia, USA), a manual system based on membrane filtration method, with conventional Pap smear. Study population included 92 patients visiting the gynecologic department under the suspicion of uterine cervical disease. In thirty of them, surgical biopsy was performed. $MonoPrep2^{TM}$ system provided well-preserved monolayer specimen with good nuclear morphology. However, about 19% of specimens were inadequate to interpret due to low cellularity. The detection rate of abnormal cells more than ASCUS (atypical squamous cells of unknown significance) was 23.9% and higher than 19.4 % of conventional Pap smear. Diagnostic concordance rate with conventional Pap smear was 81%, and severe discordance rate influencing on the management of patient was 7.6 %. Among these seven cases, $MonoPrep2^{TM}$ system was more diagnostic only in four. In comparison with histology, the sensitivity of diagnosis of $MonoPrep2^{TM}$ system was 78.9% and slightly higher than 73.5% of conventional Pap smear. However, the specificity was 81.1% and lower than 90.9% of Pap smear. In conclusion, $MonoPrep2^{TM}$ system provided diagnostic accuracies similar to the conventional Pap smear. The inexpertness of slide preparation and the low cellularity were considered to endow a limitation in more accurate evaluation.

• Journal of Nutrition and Health
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• v.30 no.10
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• pp.1229-1243
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• 1997

The purpose of this study were to :(a) investigate meal costs, plate waste costs, and advantages/disadvantages of conventional /commissary foodservices and (b) compare the effectiveness of commissary foodservice systems with that of conventional systems. Questionnaires were developed and mailed to 136 schools in Kyonggi-do. A total of 106 questionnaires were usable, resulting in a 77.9% response rate. Teacher's teaching of good food habits and students satisfaction with school foodservices were surveyed in three schools from each system. Moreover, plate waste was measured to express cost and benefit in currency. Data were analyzed using the SAS package for description analysis, t-test, $\chi$$^2$ test, ANOVA, and the Vilcoxon rank sum test. Approximately seventy percent of 294schools in Kyonggi-do were operating commissary systems and most of them were of the rural (reduced paid) type. The number of meals served varied significantly between types of foodservice. The results of this study indicated that average food , labor utility , and supply costs were saved in the commissary system and that the total meal cost/person for a day was 1218.7 won compared to 1452.4 won in the conventional system. Though total meal costs were saved in the commissary system, dietitians had difficulties cooperating with school foodservice committees and supporters associations, especially in satellites of the commissary system. In addition, dietitians and teachers in the commissary system did not carry out teaching activities on good food habits to students as often as in the conventional system. Other problems that dietitians recognized in the commissary system were difficulties in training employees and parents for portion control and serving relatively simple menus. Students, as customers of school foodservices, are very important for system evaluation . Students in the commissary system scored of food itself , cleanliness of tableware, waiting time, quantity of meal and food temperature significantly lower than students in the conventional system. Moreover , the rate of plate waste was 20.5% in the commissary system as compared to 3.3% in the conventional system. Cost-effectiveness (saving 233.7won/person/day) is the main benefit of the commissary system. However , because of lower satisfaction scores and a highest plate waste rate, 201.9won/ person were wasted in the commissary system. The results of this study suggest that increasing the number of meals served within a commissary system might maximize the efficiency of the system, but increasing the number of satellites is not recommended because it might be out of dietitians control in many aspects.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.4
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• pp.559-568
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• 2012

White (Lohmann LSL) and Brown (ATAK-S) laying hens, were reared under organic and conventional cage rearing systems, and the effects of the rearing system on performance parameters, egg production, egg characteristics, and immune response were investigated. For this purpose, a total of 832 laying hens of two commercial hybrids, i.e., 416 white (Lohmann LSL) and 416 Brown (ATAK-S) layers, were used. The experiment lasted between 23 and 70 wk of age. In this study, the white layers yielded more eggs as compared to the brown layers in both organic and conventional production systems. Egg weight exhibited a similar pattern to that of laying performance. However, the total hen-housed egg number for the white birds in the organic system was fewer than that of white birds in the conventional cage facility; conversely, a contradictory tendency was observed for the brown birds. Livability of the white layers in the organic system was remarkably lower (14%) than that of the brown line, whereas the white line survived better (3.42%) than their brown counterparts in conventional cages. The feed conversion ratio of the white hens was markedly inferior in the organic system as compared to that of the white hens in the conventional system, whereas relatively lower deterioration was reported in brown layers when reared in an organic system. The organic production system increased egg albumen height and the Haugh unit in eggs of the brown layers. The yolk color score of organic eggs was lower than that of conventional eggs for both brown and white hens. The egg yolk ratio of eggs from white layers was found to be higher in organic eggs as compared to those obtained in the conventional system. All organic eggs had heavier shells than those produced in the conventional system. Eggs from brown layers had more protein content than eggs from white layers. Neither housing systems nor genotype influenced egg yolk cholesterol concentration. When compared to conventional eggs, n-3 fatty acid content was lower in organic eggs, and the n-6:n-3 ratio was higher in organic eggs. In conclusion, two hen genotypes showed different responses in terms of performance and egg quality to two different rearing systems. A commercial white strain produced more eggs with higher egg quality as compared to a native brown strain. The brown strain was found to have adapted well to organic production conditions when survival and total egg number was taken into consideration.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.57-66
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• 1997

Successful energy conservation and good indcfor air quality (IAQ) are highly dependent on ventilation system. Air filtration is a primary solution of indoor air control strategies in terms of reducing energy consumption and improving ihdoor air quality. A conventional system with bypass filter, as it is called variable-air-volume/bypass filtration system (VAV/BPFS), is a variation of the conventional variable air volume (VAV) systems, which is designed to eliminate indoor air pollutant and to save energy. Bypass filtration system equipped with a high-efficiency particulate filter and carbon absorbent provides additional cleaned air into indoor environments and maintain good IAQ for human health. The objectives of this research were to compare the relative total decay rate of indoor air pollutant concentrations, and to develop a mathematical model simulating the performance of VAV/BPFS. All experiments were performed in chamber under the controlled conditions. The specific conclusions of this research are: 1. The VAV/BPFS system is more efficient than the VAV system in removing indoor air pollutant concentration. The total decay rates of aerosol, and total volatile organic compound (TVOC) for the VAV/BPFS system were higher than those of the conventional VAV system. 2. IAQ model predictions of each pollutant agree closely with the measured values. 3. According to IAQ model evaluation, reduction of outdoor supply air results in decreased dilution removal rate and on increased bypass filtration removal rate with the VAV/BPFS. As a results, we recommends the VAV/BPFS as an alternative to conventional VAV systems.

• Journal of Biosystems Engineering
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• v.26 no.5
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• pp.423-430
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• 2001

The purpose of this study is to develop high-speed rotary tillage system for a power tiller by improving the rotary blade and the power train of transmission. Mechanical structure of gear train of rotary drive of conventional power tiller was simplified so that power can be transmitted directly from second shaft to tilling speed change shaft by rotating freely the transfer gear which changes the direction of rotation of shafts using needle bearing installed into middle shaft. A new gear train suitable for the single-edged rotary blade and high-speed rotary drive was developed with the rotational speed of rotary shaft faster than 7.5% at 1st-speed and 1.4% at 2nd-speed the one of conventional system by changing the numbers of teeth of gears of middle shaft, tilling speed change shaft and PTO shaft. Using the developed gear train for high-speed rotary drive, field tests were performed to compare tillage performances by the developed single-edged blade and by the conventional double-edged blade. The results showed that the performances by the single-edged blade compared with the one by the double-edged blade was improved about 18% in field capacity, about 34% in fuel consumption, and 9.4% in soil crushing ratio. Therefore, it may be concluded that tillage performance by the single-edged blade was improved compared to the one by the conventional blade. Evaluation of the developed system consisting of single-edged blade and gear train for high-speed rotary drive in field revealed that tillage performance of the developed system was similar to the one of field test conducted using the system consisting of single-edged blade and gear train for rotary drive of conventional power tiller However, considering the higher cone index of the upland field where evaluation was carried out compare to the one of the ordinary paddy field, it may be concluded that tillage performance of the developed rotary tilling system better than the one of conventional system.

• Structural Engineering and Mechanics
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• v.84 no.5
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• pp.675-684
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• 2022

The conventional single-degree-of-freedom (SDOF) system is appropriate for dynamic response analysis of paneltype structures without an opening. However, the typical building structures usually have four-sided fixed walls having an opening. Therefore, it may induce a considerable error when dynamic responses are estimated based on the conventional SDOF system, since the SDOF system cannot consider the effect of an opening during the SDOF analysis. For this reason, this study proposes a new SDOF system to consider the effect of an opening by adjusting its load-mass factor. The load-mass factor can be modified based on the assumption that the behaviors of the four-sided fixed wall with an opening is very similar to the behaviors of the same size wall without an opening, when the uniformly distributed blast loaded area is identical. In order to confirm a feasibility of the proposed SDOF system, a series of numerical simulations were carried out for the four-sided fixed reinforced concrete (RC) wall under a blast load. The dynamic responses estimated from the proposed SDOF system and the conventional SDOF system were compared with the dynamic responses evaluated from the finite element (FE) analysis. Especially, for the maximum dynamic responses except for 50% opening case, the proposed SDOF system had about 1.1% to 25.7% normalized errors while the conventional SDOF system had about 4.1% to 49.1% normalized errors.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.1
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• pp.34-43
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• 2009

In this thesis, we explain developing processes of the power transmission system for lift truck. Conventional power transmission system had some problems such as spatial constraints or low speed and high torque problem. Because conventional power transmission system was mainly designed for high speed vehicles. In this paper we developed power shift drive axle specialized for $2.0{\sim}3.5$ ton lift truck. Innovative structure of transmission which is built in inside axle, enables to reduce system weight and size by 40% compared to the conventional power transmission system. Also, it is possible to do additional functions such as auto parking system and anti-roll back system.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1173-1177
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• 2004

The high investment is necessary for the new high speed lines. So the KRRI was interested in the possibility of upgrading the existing line in order to speed up the train in the conventional lines. The tilting train system has been developed because the reconstruction of railway for the cant compensation costs very high. The purpose of the tilting system is to compensate the centrifugal acceleration in order to reduce the lateral acceleration of the passenger at high speed on the curves.The pantograph of the tilting train is indispensable in order to supply the electrification equipments with power in safe. The dynamic interaction between the pantograph and the overhead catenary system causes the variation of the contact force and the contact force variation can cause contact losses, arcing and sparking. If the spark happens between the pantograph and the overhead catenary system, the EMI(electro magnetic interface) and noises may occur. After all, the quality of current collection is deteriorated. This paper deals with the active control of pantograph and presents the LQ-servo controller to reduce the contact force variation.