• 한국군사과학기술학회지
• /
• 제9권2호
• /
• pp.77-86
• /
• 2006

Usually, a tracking-gate of the tracker is used to track the target radar signal in the active ECM system. In this paper, we propose the feed-back tracking-gate filtering method. The designed method applies a tracking-gate of the tacker to the ECM system's receiver as a rejection or pass filter selected by the receiver's purpose, and the specific target signals can be passed or rejected though this tracking-gate filter. Thus, the number of input signals within the receiver's search band is minimized owing to this filter except the target signals. In conclusion, the EW equipment's reaction time can be reduced and the error value about the target signals can be lower than the previous methods'.

• 동력기계공학회지
• /
• 제6권1호
• /
• pp.82-87
• /
• 2002

Not only ferrous but also non-ferrous materials such as aluminum, brass, plastic and woods need cutting operation in recent manufacturing industry. Over the past few years a considerable number of studies have been made on non-ferrous metal cutting. But more study is required to meet various engineering needs. The purpose of this paper is to preform an experiment on the influence of feed-rate adjustment and side rake angle in turning operations from non-ferrous metals. As a result, the surface roughness was reduced when a side-rake angle increases and feed-rate decreases in the case of the plastic, brass, aluminum, and paulownia. Therefore, this papers develop a new type bite that be used to adjust side-rake angle.

• 환경영향평가
• /
• 제8권2호
• /
• pp.65-71
• /
• 1999

Characteristics of food garbage discharged from primary schools in Seoul Metropolitan city were analysed from a recycling point of view. The results of study are epitomized as follows : 1. Factors of generation of food garbage are mainly an unbalanced diet habit, indifference of class teachers, and worn-out cooking equipments. 2. Measures of reduction are principally a written message to parents, broadcasting in the school, and instructions. 3. Methods of recycling are mainly feed stuff, composting by school itself, composting on commission, and making feed stuff on commission. 4. Obstacles of food garbage recycling are a nasty smell of composting apparatus, an excessive fuel consumption of composting apparatus, a high concentration of salt, and an unstable demand for feed stuff and compost produced from food garbage. 5. Correlation factors are like follows : the number of feeding children and food garbage weight after cooking is 0.35, total food garbage generated and monthly treatment cost of food garbage is 0.20, individual school lunch expenses and food garbage weight after cooking is -0.10, individual school lunch expenses and food garbage generated per capita is 0.02, and individual school lunch expenses and monthly treatment cost of food garbage is 0.03.

• 한국산업융합학회 논문집
• /
• 제26권4_2호
• /
• pp.605-613
• /
• 2023

The multi-axis combined machining technology has enabled combined machining, which was difficult. However, the reality is that manufacturing costs are rising due to expensive equipment and there is a shortage of machine operation engineers. The purpose of this research is to present the optimum cutting conditions for the surface roughness when processing the inner diameter of SUS440C, which is an egg material, using a CNC automatic lathe. As a result of measuring the surface roughness, dry machining was the best at R_a0.481㎛ at a spindle speed of 4,000rpm, a feed rate of 0.05rev/min, and a cutting depth of 0.3mm. In wet machining, the highest value was R_a0.317 at a spindle speed of 2,000 rpm, a feed rate of 0.05 rev/min, and a cutting depth of 0.2 mm. The lower the feed rate, the better surface roughness appears. It was found that the feed rate had more influence than the number of revolutions and depth of cut.

• Asian-Australasian Journal of Animal Sciences
• /
• 제29권7호
• /
• pp.909-924
• /
• 2016

The gut is the largest organ that helps with the immune function. Gut health, especially in young pigs has a significant benefit to health and performance. In an attempt to maintain and enhance intestinal health in pigs and improve productivity in the absence of in-feed antibiotics, researchers have evaluated a wide range of feed additives. Some of these additives such as zinc oxide, copper sulphate, egg yolk antibodies, mannan-oligosaccharides and spray dried porcine plasma and their effectiveness are discussed in this review. One approach to evaluate the effectiveness of these additives in vivo is to use an appropriate disease challenge model. Over the years, researchers have used a number of challenge models which include the use of specific strains of enterotoxigenic Escherichia coli, bacteria lipopolysaccharide challenge, oral challenge with Salmonella enteric serotype Typhimurium, sanitation challenge, and Lawsonia intercellularis challenge. These challenge models together with the criteria used to evaluate the responses of the animals to them are also discussed in this review.

• 전기학회논문지
• /
• 제59권8호
• /
• pp.1489-1496
• /
• 2010

A feed forward differential architecture of analog PRML decoder is investigated to implement on analog parallel processing circuits. The conventional PRML decoder performs the trellis processing with the implementation of single stage in digital and its repeated use. The analog parallel processing-based PRML comes from the idea that the decoding of PRML is done mainly with the information of the first several number of stages. Shortening the trellis processing stages but implementing it with analog parallel circuits, several benefits including higher speed, no memory requirement and no A/D converter requirement are obtained. Most of the conventional analog parallel processing-based PRML decoders are differential architecture with the feedback of the previous decoded data. The architecture used in this paper is without feedback, where error metric accumulation is allowed to start from all the states of the decoding stage, which enables to be decoded without feedback. The circuit of the proposed architecture is simpler than that of the conventional analog parallel processing structure with the similar decoding performance. Characteristics of the feed forward differential architecture are investigated through various simulation studies.

• 대한기계학회논문집B
• /
• 제25권3호
• /
• pp.285-295
• /
• 2001

The transport phenomena in a wedge-shaped pool of twin-roll continuous caster are affected by the various operating parameters such as the melt-feed pattern, roll-gap thickness, melt-superheat, and casting speed. A computer program has been developed for analyzing the two-dimensional, steady conservation equations for transport phenomena during twin-roll continuous casting process in order to estimate the turbulent melt-flow, temperature fields, and solidification in the wedge-shaped pool. The turbulent characteristics of the melt-flow were considered using a low-Reynolds-number K-$\xi$ turbulence model. Based on the computer program, the effects of the different melt-feed patterns, roll-gap thicknesses, and superheats of melt on the variations of the velocity and temperature distributions, and the mushy solidification were examined. The results show that the liquidus line is located considerably at the upstream region, and in the lower region appear the well-mixed melt-flow and most widely developed mushy zone. Besides, the variation of melt-flow due to varying melt-feed patterns, affects mainly the liquidus line, and scarcely has effects on the solidus line in the outlet region.

• Fisheries and Aquatic Sciences
• /
• 제27권3호
• /
• pp.195-205
• /
• 2024

Amphipoda is a benthic fauna occupying aquatic environments that can be used as a live feed for mud crabs. The abundance of amphipods in the water is thought to impact the preying capacity of crablets, which in turn will affect their growth performance. This study aims to determine the preying capacity of the crablet stage of Scylla tranquebarica exposed at different densities (20, 30, and 40 amphipods / 0.5 L) of amphipod, Grandidierella megnae. The preying capacity was estimated by counting the number of amphipods ingested by an individual crablet during the 60-day rearing period. The main parameters measured were daily consumption rate (DCR), Cumulative molting (CM), Feed conversion ratio (FCR), and the specific growth rate of weight (SGR-W). The results showed that the DCR and FCR were not affected by amphipod densities but the higher the amphipod density the higher the SGR-W and CM. Based on this study, 30 amphipods / 0.5 L is recommended as the optimal density to optimize the DCR and improve the growth performance of crablets. It is also proposed that surplus live feed will potentially reduce the cannibalism rate of crablets during weaning. However, more research needs to be carried out to elucidate the benefits of crablet-feeding amphipods in communal systems.

• 한국기계가공학회지
• /
• 제18권11호
• /
• pp.1-8
• /
• 2019

In this study, we design the feed system and process conditions for a lamp garnish lens of an automobile. For this purpose, four design alternatives are presented and injection molding simulation analyses are performed. The optimal feed system is selected by considering the formability of the product and the cost of mold manufacture. The product formability is assessed by the weld line, warpage, sink mark and the maximum injection pressure, whereas the mold-making cost is estimated by the number of valve gates in the hot runner system. To improve the product formability, process conditions are optimized using an experimental design approach named one-factor-at-a-time. No weld line is generated as a result of the optimization. In addition, it is found the warpage and sink mark are reduced while the maximum injection pressure is increased, compared with those before the optimization.

• 농업과학연구
• /
• 제42권4호
• /
• pp.389-396
• /
• 2015

This study was performed to investigate the opinions of various related-industries on ban of antibiotics growth promoters (AGPs) in commercial mixed feed. The answers on a total of 21 questions were summarized by response number and percentage. 93% of those surveyed were in agreement of a ban of dietary AGPs. The agreement reasons were the livestock safety (61.5%), the reduction of antibiotic use (23.1%), and decrease of antibiotic-resistant bacteria (11.5%). The negative effects expected by the ban of AGPs were poor growth performance (44.2%), elevated disease emergence (31.4%), increasing the feed cost (18.6%), and quality degradation of livestock (5.8%). As the efficient plans for decline of AGPs use, the feeding environment improvement was the highest with 43%, and farmer training and the consolidation inspection of residual substance on antibiotics in livestock product was 27.9% and 22.1%, respectively. 46.5% of respondent are considering the modification of feed spec and 39.5% of those surveyed have staged a modified feed spec. In conclusion, livestock related-industries approve a ban of AGPs, and they assert that the policy support, improvement of management and environment in the farm, providing technology from related-industries are multiply essential for a stable settlement of a ban policy of AGPs.