• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.234-236
• /
• 2003

In this paper, a new control scheme of Class-E inverter for reducing the crest factor of electronic ballasts for fluorescent lamps using Pulse-Frequency-Modulation (PFM) is introduced The lifetime of the lamps is guaranteed by decreasing the lamp crest factor and voltage stress of the switch is significantly decreased by a new scheme although conventional Class-E inverter is used in this paper The proposed PFM control scheme doesn't used any auxiliary circuit. The proposed control strategy is executed by feeding back the input current. and the Zero-Voltage-Switching (ZVS) is ensured by operating beyond resonant frequency. Therefore, the control principles of proposed method are explained in detail and its validity is verified through several simulated results.

• Journal of Power Electronics
• /
• 제3권3호
• /
• pp.175-184
• /
• 2003

In this paper, a new control scheme of Class-E inverter for reducing the crest factor of electronic ballasts for fluorescent lamps using Pulse-Frequency-Modulation (PFM) is Introduced The lifetime of the lamps is guaranteed by decreasing the lamp crest factor and also voltage stress of the switch is significantly decreased by a new scheme although conventional Class-E Inverter is used In this paper. The proposed PFM control scheme didn't use any auxiliary circuit. The proposed control strategy is executed by feeding back the Input voltage, and the zero-voltage-switching (ZVS) is ensured by maintaining constant turn-off time of the switch Therefore, the control principles of proposed method are explained in detail and its validity is verified through several simulations and experimental results.

• Journal of Power Electronics
• /
• 제16권1호
• /
• pp.173-181
• /
• 2016

In this paper, a new technique for harmonic optimization in cascaded H-bridge 7-level inverters is proposed. The suggested strategy is based on minimizing an objective function which simultaneously optimizes the converter utilization and Total Harmonic Distortion (THD). The Switch Utilization Ratio (SUR) is formulized for both the phase and line-line voltages of a 7-level inverter and is considered in the final objective functions. Based upon the SUR formula, utilization ratio enhancement will reduce the value of feeding DC links, which improves the efficiency and lifetime of the circuit components due to lower voltage stresses and losses. In order to achieve more effective solution in different modulation indices, it is assumed that the DC sources can be altered. Experimental validation is presented based on a three-phase 7-level inverter prototype.

• Journal of Power Electronics
• /
• 제19권5호
• /
• pp.1153-1161
• /
• 2019

A current sharing controller is proposed in this paper for parallel-connected converters. The proposed controller is based on the calculation of the magnitudes of system current space vectors. Good current distribution between parallel converters is achieved with only one Proportional-Integral (PI) compensator. The proposed controller is analyzed and the circulating current impedance is derived for paralleled systems. The performance of the new control strategy is experimentally verified using two parallel connected converters employing Space Vector Pulse Width Modulation (SVPWM) feeding a passive RL load and a 2.2 kW three-phase induction motor load. The obtained test results show a reduction in the current imbalance ratio between the converters in the experimental setup from 53.9% to only 0.2% with the induction motor load.

• Animal Bioscience
• /
• 제36권2_spc호
• /
• pp.374-384
• /
• 2023

Skeletal muscle metabolism regulates homeostatic balance in animals. The metabolic impact persists even after farm animal skeletal muscle is converted to edible meat through postmortem rigor mortis and aging. Muscle metabolites resulting from animal growth and postmortem storage have a significant impact on meat quality, including flavor and color. Metabolomics studies of postmortem muscle aging have identified metabolisms that contain signatures inherent to muscle properties and the altered metabolites by physiological adaptation, with glycolysis as the pivotal metabolism in postmortem aging. Metabolomics has also played a role in mining relevant postmortem metabolisms and pathways, such as the citrate cycle and mitochondrial metabolism. This leads to a deeper understanding of the mechanisms underlying the generation of key compounds that are associated with meat quality. Genetic background, feeding strategy, and muscle type primarily determine skeletal muscle properties in live animals and affect post-mortem muscle metabolism. With comprehensive metabolite detection, metabolomics is also beneficial for exploring biomarker candidates that could be useful to monitor meat production and predict the quality traits. The present review focuses on advances in farm animal muscle metabolomics, especially postmortem muscle metabolism associated with genetic factors and muscle type.

• 한국미생물·생명공학회지
• /
• 제28권2호
• /
• pp.105-110
• /
• 2000

강력한 함암작용을 나타내는 단백다당체를 생산하는 Phellinus linteus WI-001 균주를 대상으로 배양학적 특성 및 초기 배양배지의 탄소원인 glucose 농도에 따른 균사체 생산성을 조사하였다. 배양중 최적 pH와 온도는 각각 5.5와 28$^{\circ}C$인 것으로 나타났다. 특히 pH의 경우 전 배양기간에 걸쳐 5.5에서 6.5의 비교적 좁은 범위에서 변화하였다. 초기 glucose 농도를 0.5%, 1%, 2%, 3% 및 4%에서 균사체 생산량 및 세포비성장속도를 조사한 결과 최종 균사체 생산량은 glucose 농도가 증가할수록 높게 나타났으나, 세포비성장속도가 가장 빠르게 나타나는 초기 1% glucose 조건하에서 배양하다가 추가로 glucose를 간헐적 또는 지속적으로 공급하는 전략으로 생산성 향상을 시도하였다. 그 결과 회분식 배양에 비해 간헐적 공급방식에서는 28% 지속적 공급방식에서는 42%의 수율이 증가되었다.

• 산업공학
• /
• 제11권3호
• /
• pp.193-207
• /
• 1998

The agriculture and fishery share in the Korean GDP is continuously decreasing after 1960s. Furthermore the proportion of these industries in the GDP has diminished as low as 10 percent in recent years. However, the stockbreeding sector in these industries are considerably expanded. More than 50 percent of the whole farmhouses are involved in the livestock farming, and the stock farming portion is steadily increased in its size and scope. Thus, the mechanization and the automization of stockbreeding equipments are greatly required to reduce down production cost, as well as to win the competitiveness in the global market. From this aspect, developed in this paper is a stockbreeding management system (SMS) for dairy cattle, which can be used in small and medium sized dairy farms. First, the basic schema of the stockbreeding management system are addressed in view of stockbreeding management for individual dairy cattle. Electronic identification (EI) systems and sensory devices have changed stockbreeding management strategy from group stock control into individual stock control manner. The SMS receives stock body measurement data through the sensory devices such as weight, temperature, and milk conductivity meters. A common database then integrates those measuring data together so that the SMS can determine the appropriate solution on each stock's breeding such as feeding and milking. Thus, each stock can be supervised by a sophisticated SMS that provides the best solution to the stockbreeding throughout the stock's whole life-cycle. Secondly. six major submodules of the SMS, based on the EI and sensory devices, are proposed. They are individual stock management, disease management, health management, feeding management, milking management, and a propagation management submodule. Finally, a prototype system for the SMS is demonstrated. The system is developed using Delphi 2 client-server system run under the Windows 95 environment.

• 한국어류학회지
• /
• 제25권3호
• /
• pp.163-168
• /
• 2013

통영주변해역에서 2010년 1월부터 8월까지 낚시, 자망 그리고 새우조망을 이용하여 돌가자미 102개체와 줄가자미 101개체를 채집하고 위내용물을 분석하였다. 각각의 위내용물 분석 결과 돌가자미는 이매패류와 어류가 대부분을 차지하였고, 줄가자미는 거미불가사리류가 위내용물의 대부분을 차지하여 저서성 육식어류로 나타났다. Prey-specific abundance 분석 결과 다른 가자미과 어류들과 비교하여 깊은 수심에 서식하는 돌가자미와 줄가자미는 각각 이매패류와 거미불가사리류에 섭식이 특화된 specialist predator로 나타났다. 돌가자미와 줄가자미는 같은 지역에 출현하는 유사종 사이에서 나타날 수 있는 먹이경쟁을 피하기 위해 서로 다른 식성을 가지는 것으로 판단할 수 있다.

• 한국컴퓨터정보학회논문지
• /
• 제12권2호
• /
• pp.265-279
• /
• 2007

본 연구는 배합사료업체와 고객기업(축산농가) 간의 거래관계에서 고객만족과 계속 재구매 의도(충성도)에 영향을 미치는 공급서비스 관행을 규명하였다. 공급서비스 관행들을 선행연구 고찰결과에 따라 기술적 품질의 공급서비스와 기능적 품질의 공급서비스로 분류하고 이들 각각이 고객만족과 계속 재구매 의도(충성도)에 어떠한 영향을 주는가를 실증분석을 하였다. 실증 분석한 결과 한국의 배합사료공급에 있어서 기술적 품질의 공급서비스는 고객충성도에 긍정적 영향을 주고 기능적 품질의 공급서비스는 고객만족과 고객충성도 모두에 긍정적 영향을 주는 것으로 나타났다.

• 한국축산시설환경학회지
• /
• 제5권3호
• /
• pp.189-196
• /
• 1999

Anaerobic digestion is a naturally occuring microbial process involving the decomposition of organic materials such as livestock manure. This study explores the effect of the operating conditions, HRT (Hydraulic Retention Time) and feeding frequency on treatment efficiency for digestion of pig slurry, which has been one of most difficult organic waste for proper treatment in livestock production industry in Korea at the present time. The pilot-scale CSTR of 5 m3 in volume was designed. manufactured, and operated at the temperature of 35$\pm$1$^{\circ}C$. The digester was designed to hydraulically stir for complete mixing and to supply heat from the water bath to maintain mesophilic temperature. The HRT of the digester for Test 1 and Test 2, and Test 3 was set for 17 days and 13 days respectively and pig slurry was fed once a day with 300$\ell$ each for Test 1 and Test 3, while twice with 150$\ell$each for Test 2. Test 2 showed better performance by increase of 4% in VS removal efficiency and 5% in biogas production rate. This is mainly attributed to smaller temperature drop by feeding frequently with half amount, which eventually led to lesser impact on anaerobic mocrobes in the digester. Test 2 maintained optimum pH 7.8 which uplifted the activaton of sulfur-reduction bacteria, alkalinity of around 4,000mg/$\ell$, VA of over 3,000mg/$\ell$ for whole period of experiment. Further research may require to provide the practical operation strategy of anaerobic treatment system for treatment of pig slurry.