• Proceedings of the KIPE Conference
• /
• 1997.07a
• /
• pp.14-20
• /
• 1997

Due to several advantages of Pulse Width Modulated(PWM) Converter, such as unity power factor with low-harmonics and energy regeneration, PWM converter has been widely used in industrial application. In every application of energy conversion equipment, the design and implementation must be carried out considering performance and cost. High quality with low cost is the best choice for energy conversion equipment. High dc link voltage can reduce inverter and motor side losses and system dimension compare to low dc link voltage. Analog controller can make PWM converter cheaper without considerable degradation of the performance than digital controller. This paper shows the simplified analog controller-for 600V dc link voltage using stationary reference frame control and the simulation results.

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.696-699
• /
• 2004

This paper proposes the Low Cost Class-E Converter with Power Conversion Operation of Piezoelectric Transformer. The Power Piezoelectric transformer capacity used in the proposed circuit is 15W and the electric equivalent circuit is presented. Class E type converter has some merits such as small component count, small size, and low cost. The topology has also ZVS conditions for main switch, thus in efficiency aspect, it is also competitive for commercial feasibility. The analysis and design guideline are suggested and also they are verified by experimental results.

• Proceedings of the KIPE Conference
• /
• 2012.11a
• /
• pp.5-6
• /
• 2012

In this paper, a simplified maximum power point tracking technique for the solar charger is presented. Main advantages of the proposed charger include low cost and optimized charge time. The maximum power point tracking method is used to deliver the maximum power from PV array to the battery thereby reducing the charge time. Moreover, the proposed technique which tracks the maximum power point by adjusting output current helps reduce the quantity of required number of sensors for the charger. The experimental protype was implemented by using an 80W PV array, a buck converter and a digital signal processor to verify the feasibility of the proposed method.

• Asian-Australasian Journal of Animal Sciences
• /
• v.4 no.2
• /
• pp.187-193
• /
• 1991

Almost 1/4 of all the coconuts in the world is produced in the Philippines. During periods of high supply of coconuts it would be better to feed coconut meat to farm animals for conversion into meat and eggs. Three studies were conducted at the Visayas State College of Agriculture, Baybay, Leyte, Philippines from April, 1983 to April, 1985 to determine the response of Mallard ducks, Muscovy ducks and broilers to fresh coconut meat supplementation in their diets. Results showed that Mallard ducks on ration with coconut meat performed similarly with those on ration without coconut meat. Feed cost per dozen eggs was reduced by 28-30% with coconut meat. Feed cost per unit gain of muscovy ducks was reduced by 32-37% by coconut meat supplementation. With broilers, feed conversion, gain in weight and breast weight were significantly improved by coconut meat supplementation. Return-above-feed cost increased with increasing level of coconut meat in the ration.

• Asian-Australasian Journal of Animal Sciences
• /
• v.8 no.5
• /
• pp.427-431
• /
• 1995

This study was carried out to investigatigate feed cost of com-manure silage and growth performance of Korean native goats which was fed com-manure silage. The average weight about 11.6 kg of twenty one Korean native male goats (4 months used to determine the effect of the feeding trial. The goats were individually reared in metabolism cages and fed diet daily of 2% of the body weight on the dry matter basis. The treatments were divided into whole crop com silage(CS silage), whole crop com ensiled with cage layer manure (CLM; Com-manure silage or MS silage) and whole crop com silage supplemented with urea at feeding time (US silage). The content of crude protein, lactic acid and the ratio of ammonia nitrogen to total nitrogen ($NH_3-N/Total$ N) in MS silage were increased from 7.7 to 14.9%, 5.7 to 7.5% and 8.2 to 16.6%, and the differences were significantly (p < 0.05) different in all observations. Total body weight gain of those goats for 90 days was 6.0 kg (66.7 g/day; MS silage 4.3 kg (47.8 g/day; US silage) and 3.9 kg (43.4 g/day; CS silage), and feed conversion of MS silage (5.98) for 90 days was increased by far the best in the other groups and decreased about 30% in proportion to CS silage. Feed cost per 1 kg MS silage (1,606 won) was the lowest (p < 0.05) in the body weight gain and cut down expenses than fed CS silage by 37% of feed cost.

• Journal of Digital Contents Society
• /
• v.15 no.2
• /
• pp.289-300
• /
• 2014

Cloud computing helps users to save a significant amount of cost that is related to infrastructure investment, management, and maintenance. In this paper, we study the conversion planning from campus legacy web servers into an integrated cloud computing web server system. We also analyze the conversion profit when campus web servers are integrated into a cloud computer. We first investigate the cost of legacy system model of campus web servers operated by individual laboratories, departments, institutes and so on. Next, we set up a cloud computer model for the integrated web services meeting the same performance requirements. Then, we derive the conversion profit. From the result of the derivation, we see that the conversion can be effectively applied to and adopted by mid or large sized campuses and similar institutions that provide web services.

• Carbon letters
• /
• v.17 no.1
• /
• pp.1-10
• /
• 2016

Lignocellulosic biomass conversion to biofuels such as ethanol and other value-added bio-products including activated carbons has attracted much attention. The development of an efficient, cost-effective, and eco-friendly pretreatment process is a major challenge in lignocellulosic biomass to biofuel conversion. Although several modern pretreatment technologies have been introduced, few promising technologies have been reported. Microwave irradiation or microwave-assisted methods (physical and chemical) for pretreatment (disintegration) of biomass have been gaining popularity over the last few years owing to their high heating efficiency, lower energy requirements, and easy operation. Acid and alkali pretreatments assisted by microwave heating meanwhile have been widely used for different types of lignocellulosic biomass conversion. Additional advantages of microwave-based pretreatments include faster treatment time, selective processing, instantaneous control, and acceleration of the reaction rate. The present review provides insights into the current research and advantages of using microwave-assisted pretreatment technologies for the conversion of lignocellulosic biomass to fermentable sugars in the process of cellulosic ethanol production.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.717-721
• /
• 2010

Soil volume conversion factors are used for estimation of an excavated the soil volume which will be removed or added in levelling the ground surface of a construction site. An accurate evaluation method will help us reduce a construction cost and time consuming. In this study, we performed the laboratory tests, including grain size measurement, water content, specific gravity, porosity, density and XRD tests, to suggest reliable soil volume conversion factors and weathering indices in field using nondestructive methods. The weathering index and soil volume conversion factor L are obtained for different types of soils. At results, the CIW index is the best method measuring the weathering index and the factor L is relative to natural porosity, void ratio, density and dry density.

• Journal of Oriental Neuropsychiatry
• /
• v.13 no.2
• /
• pp.225-232
• /
• 2002

Conversion disorder has difficulties of clinic discriminationis. If it is possible at the early stage, rehabilitation time and cost will be reduced. This case is that of motor and sensory disorder. The clinic progress has well showed the characters of conversion disorder. This study will be helpful for the understanding of the conversion disorder.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2002.11a
• /
• pp.9-14
• /
• 2002

Direct-conversion receiver(DCR) architecture has superior advantages in size, cost, and power over superheterodyne receiver architectures. However, the use of direct-conversion receiver architecture has been limited due to the direct-current offset noise. The ac coupling, which is used to overcome the direct-current offset noise, causes an inter-symbol interference(ISI), whose effects can be effectively mitigated using an equalizer. In this paper, the performance of a direct-conversion receiver with ac coupling in the presence of direct-current offset is analyzed via computer simulation. The simulation result shows that by using decision feedback equalizer with LMS(Least Mean Square) algorithm, signal-to-noise ratio loss of the direct-conversion receiver compared to the idea receiver can be reduced to less than 1㏈ for corner frequencies as large as 10% of the symbol rate.