• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
• /
• pp.1081-1082
• /
• 2006

The more feeding distance of substation is long and travel vehicle increases in feeding section, power supply leaches the limits. And if it exceeds the limit, it causes a serious trouble for train operation. Therefore, it is designed that the number of train increases constantly until 2030. So consistent power supply according to the increasement of vehicle in power system at present Seoul-Pusan high speed railway, regular operation in case of extended feeding occurring accidents in substation, and the least headway scheduled at relevant section and the effects installing compensation facility in case of impossible extended feeding is examined.

• 농업과학연구
• /
• 제44권3호
• /
• pp.375-383
• /
• 2017

This study was conducted to investigate the effects of sex, environmental factors, and feeding system on the carcass traits of Hanwoo (Korean Native Cattle). Data were collected from 7,866 heads slaughtered in Chungnam province during one-year period. Using the collected carcass traits data which greatly influence a Hanwoo's carcass grade, the effects of sex class, slaughter season, and feeding system were estimated. Backfat thickness of steers was significantly higher than that of bulls (p < 0.05). Marbling score was also the highest in steers when compared with cows and bulls (p < 0.05). Live weight and carcass weight were significantly higher in winter than in summer (p < 0.05). However, backfat thickness was significantly lower in summer than in other seasons (p < 0.05). Marbling score was higher in spring and fall than in summer and winter (p < 0.05). In terms of feeding systems, TMR (Total mixed ration) and TMF (Total mixed fermentation feed) fed groups showed the highest carcass grade (p < 0.05). However, the group fed TMR and formula feed at the final fattening period showed the lowest performance (p < 0.05) and it is assumed that some stress was associated to the feed change. The results reconfirm that castration may be recommended in order to improve meat quality and marbling scores in bulls. There was no consistent trend of seasonal effects of slaughter on carcass traits although some traits were significantly affected. Regarding the feeding system, either TMR or TMF can be supplied to achieve high feed efficiency and good carcass characteristics in Hanwoo.

• 한국수산과학회지
• /
• 제47권5호
• /
• pp.582-587
• /
• 2014

We investigated the effects of feeding rate on the growth, blood components, and histology of sub-adult olive flounder Paralichthys olivaceus. Optimum feeding rate (initial fish mean weight : $384.2{\pm}5.91g$) was determined under the optimum water temperature. Two replicated groups of fish were fed a commercial diet at rates of 0%, 0.3%, 0.5%, and 0.7% body weight (BW) per day, and to satiation. The feeding trial was conducted using a flow-through system with ten 1.2-metric ton aquaria receiving filtered seawater at $20-24.5^{\circ}C$ for 3 weeks. After the feeding trial, the weight gain (WG) and specific growth rate (SGR) were significantly higher in fish fed at 0.7% BW/day and those fed to satiation (0.9% BW/day) than in fish fed at other feeding rates or in the unfed fish. These parameters were negative and significantly lower in the unfed fish than in those fed the experimental diet at all feeding rates. There were no significant differences in WG and SGR among fish fed at 0.3 and 0.5% BW/day and among those fed at 0.7% BW/day and to satiation. The histological changes in the hepatopancreas, kidney, and anterior intestine of fish fed at 0, 0.5, and 0.9 % BW/day did not differ much. Broken-line regression analysis of weight gain showed that the optimum feeding rate of olive flounder weighing 384 g was 0.74% BW per day at the optimum water temperatures.

• 한국산학기술학회논문지
• /
• 제18권3호
• /
• pp.232-241
• /
• 2017

본 논문에서는 대형화되고 기업화되어가고 있는 국내 축산농가를 위한 AGV와 스크류컨베이어 기반의 자동 소사료 공급시스템에 대해 소개한다. 제안된 자동 소사료 공급시스템은 최상단에 펠렛형 혼합 사료가 적재되는 호퍼부, 호퍼부에서 펠렛형 혼합사료를 배출부로 이송시키는 스크류컨베이어를 장착한 이송부, 벨트컨베이어로 구성된 배출부 및 시스템 이동을 위한 전자 유도선 주행방식의 AGV로 구성되어있다. 적재된 사료 무게는 이송부의 하부에 위치한 로드셀에 의해 측정된다. 개별 우사 셀에 설치되는 RFID TAG에 미리 저장된 사료 배출정보를 시스템이 읽어 정해진 양만큼의 사료를 시스템이 주행하면서 배출하게된다. 공급 배출 테스트시스템을 제작하여 사료의 공급 능력을 결정짓는 사료 이송부의 스크류 외경, 스크류 샤프트 외경, 스크류 피치 간격 등을 포함하는 스크류컨베이어 설계인자 도출을 하였으며 도출된 설계인자들을 최종 공급시스템 제작 시에 적용하였다. 사료 급이시스템을 제어하기 위해 DSP기반의 주제어기 및 공급시나리오에 따른 급이알고리듬도 함께 개발되었다. 실험을 통해 국내 우사에 사료공급조건을 만족시키기 위해 설정된 목표인 5 m의 거리를 0.1 m/sec의 속도로 주행하면서 7 마리가 수용되는 한 개의 우사에 필요한 총 21 kg의 사료를 초당 420 g으로 균일하게 공급이 가능함을 확인하여 개발된 축우용 무인사료공급시스템이 규격화된 국내 축산농가에 적용될 수 있는 가능성을 확인하였다.

• 전기학회논문지
• /
• 제56권1호
• /
• pp.1-7
• /
• 2007

Generally, an electric railroad feeding system has many problems due to the different characteristics in contrast with a load of general three-phase AC electric power system. One of them is harmonics problem caused by the switching device existing in the feeding system, and moreover, the time-varying dynamic loads of rail way is inherently another cause to increase this harmonics problem. In Korea power systems, the electric railroad feeding system is directly supplied from the substation of KEPCO. Therefore, if voltages fluctuation or unbalanced voltages are created by the voltage and current distortion or voltage drop during operation, it affects directly the source of supply. The trainloads of electric railway system have non-periodic but iterative harmonic characteristics as operating condition, because the electric characteristic of the electric railroad feeding system is changed by physical conditions of the each trainload. According to the traditional study, the estimation of harmonics has been performed by deterministic way using the steady state data at the specific time. This method is easy to analyze harmonics, but it has limits in some cases which needs an assessment of dynamic load and reliability. Therefore, this paper proposes the probabilistic estimation method, moments matching method(MW) in order to overcome the drawback of deterministic method. In this paper, distributions for each harmonics are convolved to obtain the moments and cumulants of TDD(Total Demand Distortion), and this can be generalized for any number of trains. For the case study, the electric railway system of LAT(Intra Airport Transit) in Incheon International Airport is modeled using PSCAD/EMTDC dynamic simulator. The raw data of harmonics for the moments matching method is acquired from simulation of the LAT model.

• Fisheries and Aquatic Sciences
• /
• 제24권6호
• /
• pp.219-227
• /
• 2021

The effects of various feeding ratios on the growth, body composition, and blood chemistry of the juvenile mandarin fish Siniperca scherzeri (initial body weight 9.6 g) were examined in recirculating freshwater system equipped with 21, 300 L tanks at 20 fish per tank. The triplicate groups of seven feeding ratios treatments were prepared: 100% (control), 95%, 90%, 85%, 80%, 75%, and 70% of satiation. The feed amount of control group was determined by supplying with apparent satiation and then the feed amounts of the other six feeding groups were determined based on the feed amount of the control group. Fish were hand-fed with test diet (55.4% crude protein) for 10 weeks. Weight gain (WG) and specific growth rate of fish fed to 100% satiation were not significantly (p > 0.05) different from those of fish fed to ≥ 80% satiation but were significantly higher than those of fish fed to 75% and 70% satiation. Feed efficiency, protein efficiency ratio, and protein retention of 100% satiation were not significantly different from those of 95% and 90% satiation but were significantly (p <0.05) lower than ≤ 85% satiation. Condition factor, hepatosomatic index, and coefficient variation were not significantly (p > 0.05) affected by feeding ratio. Whole body composition and contents of hematocrit, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, glucose, total protein, and high-density lipoprotein cholesterol in blood serum were not significantly (p > 0.05) affected by the feeding ratio; however, content of total cholesterol tended to decrease as the feeding ratio decreased. Using broken-line analysis of WG, it was suggested that the optimum feeding ratio of juvenile mandarin fish, ranging from 9.0 g to 37.0 g, appeared to be 87.7% of satiation without growth inhibition.

• Journal of Biosystems Engineering
• /
• 제16권2호
• /
• pp.148-158
• /
• 1991

This study was undertaken to develop the feed rate control system for the head feed thresher by making use of the microprocessor and to evaluate the response of the system to a various threshing conditions. It was verified the performance of the control system through experiments. Control conditions were determined based on the simulation results of control system. The control system set at RH=500rpm, RL=480rpm for the bundle feed was considered optimum to give a high threshing capability and still to stabilize the feeding seed regardless of the bundle size. The control system for the continuous spread feed set at the range of LH=15mm, and LL=12mm gave a high control performance for the feeding mass of 1.1Kg/m and lower tested. In addition, the feed rate proportionality constant should be set lower than one in order to keep the rotational speed of threshing cylinder within the range of 500~520rpm.

• 한국식품영양학회지
• /
• 제31권1호
• /
• pp.52-61
• /
• 2018

The purpose of this study is to examine the feeding and nutritional status of enteral tube-fed elderly patients. Subjects included 77 elderly hospitalized patients who had received enteral nutrition more than one week before admission. Medical records on admission and actual feeding volume were used to assess anthropometric, biochemical, and nutritional status. Most patients manifested disorders of the nervous system (93.5%) and the average duration of tube feeding was 13.9 months. The average feeding volume of formula was 1,107 mL per day and the mean ratios of calorie and protein (supplied vs. required) were 81.7% and 80.9%, respectively. At admission, 57.4% of the patients were malnourished according to the institutional criteria. Patients receiving less than 80% of the required calories were in worse nutritional status compared with those receiving more than 80% of the required calories. Body mass index, percent ideal body weight, serum albumin level and blood lipid levels (total cholesterol, HDL-cholesterol, triglyceride) were significantly lower in patients receiving less than 80% of the required calories. These results indicate the high prevalence of malnutrition and the need for increased attention and nutritional care of elderly patients undergoing long-term enteral nutrition.

• 전기학회논문지
• /
• 제65권6호
• /
• pp.1108-1114
• /
• 2016

The cause of failure in the AT feeding system is divided into grounding, short-circuit of feeding circuit and internal faults of the railway substation. Since the fault current is very high, real-time current is detected and the failure must be immediately removed. In this paper, a new DC offset elimination filter that can remove component to decrease in the form of exponential function using low-pass filter was proposed in order to extract the fundamental wave from distorted fault current. In order to confirm the performance of the proposed filter method, AT feeder system was modelled by simulation tool and simulations were performed under various conditions such as fault location, fault resistance and fault voltage phase angle in case of trolley-rail short-circuit fault. When applying the proposed DC-offset removal method, it can be seen that the phase delay and gain error did not appear.

• Journal of Electrical Engineering and Technology
• /
• 제8권1호
• /
• pp.118-123
• /
• 2013

This paper presents performance comparison between concentrated winding and distributed winding of IPMSM (Interior Permanent Magnet Synchronous Motors) which is recently used for light-weight railway applications. Motors are designed on various schemes and analyzed by using FEM (Finite Element Method) instead of EMCNM (Equivalent Magnetic Circuit Network Method) in order to take into account saturation and non-linear magnetic property. The overall performance such as torque, torque ripple, losses, demagnetization, efficiency, power density and so on are investigated in detail at the rated and maximum operating speed. The results of the analysis found that both concentrated and distributed winding IPMSMs are promising candidates for high power railway traction motor.