• Proceedings of the Acoustical Society of Korea Conference
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• 1991.06a
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• pp.151-156
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• 1991

In this paper, we propose a new algorithm for designing the R-G filter that has optimum performance in terms of mean square sidelobe level(MSSL) for the Barker code. The advantage of the conventional R-G filter lies in its simple structure so that it can be easily implemented. However, the conventional R-G filter dose not have optimum performances in terms of peak sidelobe level(PSL), mean sidelobe level(MSL), and MSSL. Recently, a(R-G)LP filter of which filter coefficients are obtained by the linear programming algorithm was proposed and known to have optimum performance in PSL. The proposed (R-G)LS filter keeps the simple structure of the conventional R-G filter and has the filter coefficients that minimizes the sidelobe in the least square sense. The analytic results show that the proposed (R-G)LS filter has better performances than the conventional R-G filter in terms of PSL, MSL, and MSSL. Compared with (R-G)LP filter, the proposed (R-G)LS filter has better performances in terms of MSL and MSSL. The proposed filter design algorithm can be applied to the other binary codes such as truncated pseudonoise(PN) codes and concatenated codes.

• Environmental Engineering Research
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• v.10 no.3
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• pp.105-111
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• 2005

The applicability of the USEPA's (United States Environmental Protection Agency) three criteria of enhanced coagulation (criterion 1-TOC level less than 2 mg/l. before chlorination; criterion II-% requirement of TOC removal; criterion III-point of diminishing return) for Korean waters was evaluated in this study. This study also investigated an effect of enhanced coagulation on turbidity removal, and attempted to identify the best coagulant for enhanced coagulation. Three different waters were used in this study: one river water and two lake waters. five different coagulants were used: alum, liquid alum, PACl, ferric chloride with and without water. Results of this study showed that all three criteria were achievable for the tested waters. For these waters, controlling criterion was found to be different depending upon raw water characteristics. When initial Toe level was low(< 4 mg/L), criterion I (< 2 mg/L) could be the controlling criterion. As TOC level increased, criterion II (% TOC removal) became the controlling criteria. It was possible to achieve different goals of turbidity and TOC removals. Although the optimum region of TOC removal was more acidic than that of turbidity removal, there was no conflict between these two removals. The best coagulant was found to be different depending upon the evaluation tool: maximum and optimum removal. ferric chloride was more effective than alum in terms of the maximum TOC removal, while Al-based coagulant such as alum or PACl was the best coagulant in terms of the optimum TOC removal.

• Nuclear Engineering and Technology
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• v.54 no.9
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• pp.3235-3241
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• 2022

The Korea Atomic Energy Research Institute (KAERI) is planning the construction of the KIJANG Research Reactor (KJRR) for stable supply of ⁹⁹Mo. The Fission ⁹⁹Mo Production Process (FMPP) of KJRR produces solid waste such as spent uranium cake and alumina cake, and liquid waste in the form of intermediate level liquid waste (ILLW) and low level liquid waste (LLLW). This study thus established the operating range and optimum operating conditions for the cementation of ILLW from FMPP. It also evaluated whether cement waste form samples produced under optimum operational conditions satisfy the waste acceptance criteria (WAC) of a disposal facility in Korea (Korea radioactive waste agency, KORAD). Considering economic feasibility and safety, optimum operational conditions were achieved at a w/c ratio of 0.55, and the corresponding salt content was 5.71 wt%. The cement waste form samples prepared under optimum operational conditions were found to satisfy KORAD's WAC when tested for structural stability and leachability. The results indicate that the proposed cementation conditions for the disposal of ILLW from FMMP can be effectively applied to KJRR's disposal facility.

• Journal of Aquaculture
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• v.12 no.2
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• pp.145-153
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• 1999

This study was conducted to determine the protein requirement of ayu (Plecoglossus altivelis). Two replicate groups of fish initially averaging 6.6 g were fed the five isocaloric diets containing different protein level from 29% to 57% in a flow-through freshwater system for 25 days. White fish meal was used as a sole protein source. Weight gain and feed efficiency of fish increased significantly with dietary protein level up to 43% (P＜0.05) with no additional response above this level. Protein and lipid retention, moisture, protein and lipid contents of body were not affected by dietary protein levels (P>0.05). Daily protein intake increased significantly with dietary protein level, whereas protein efficiency ratio of fish fed the 57% dietary protein decreased (P<0.05). The data obtained in this study indicate that a 43% dietary protein level could be recommended for the optimum growth of ayu.

• International Journal of Highway Engineering
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• v.17 no.3
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• pp.27-33
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• 2015

PURPOSES : To ensure appropriate RCC properties with sufficient strength development and workability, it is necessary to secure a proper level of consistency. It is also necessary to secure maximum dry density, which is an important factor for increasing the interaction of aggregate interlocking, leading to an augmentation of RCC strength. On the other hand, the dry density of RCC can be changed owing to the compaction conditions, water content, and particle size distribution. A Proctor test and a modified Proctor test were used for determining the optimum water content needed to achieve maximum dry density with different amounts of compaction energy. A Vebe test, on the other hand, was used for checking the level of consistency, which is important for producing a workable mixture. METHODS : To confirm the degree of compaction at various particle sizes, RCC mixtures with different sand/aggregate ratios were evaluated. The Proctor test and modified Proctor test were applied to these mixtures to check the effect of the aggregate gradation and compaction energy on the maximum dry density and optimum water content. During each test, three specimens were produced for all types of water content under each aggregate gradation. A compaction curve and the optimum water content and maximum dry density for each aggregate gradation were then obtained for both tests. The range of water content for the appropriate consistency of each aggregate gradation was determined through a Vebe test. The optimum water content was then evaluated based on this range. RESULTS : The compaction test results show that the modified Proctor test provides a higher maximum dry density and lower optimum water content compared with the standard Proctor test. For the modified Proctor test, two cases of aggregate gradation (s/a = 30% and 70%) had the optimum water contents outside of the appropriate water content range. For the standard Proctor test, on the other hand, none of aggregate gradations provided the optimum water content within the desired range. CONCLUSIONS : The modified Proctor test should be used for an RCC mixture design because it can provide adequacy between maximum dry density and consistency. Moreover, the compaction roller has become highly developed for higher compaction energy.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.1
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• pp.72-86
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• 1990

This study was carried out to get the basic information of irrigation plans for upland crops such as the optimum irrigation level and the project water requirement. Red peppers and cucumbers were cultivated in PVC pot lysimeters filled with 60cm deep clay loam soil. Four tensiometers were installed in each pot to measure the soil water pressure head. Six levels of irrigation were used. The results obtained from this study are summarized as follows: 1.The optimum irrigation level. The irrigation level of FC-PF2.7 was found to be the optimum level for both red pepper and cucumber with respect to the yield and the weight per fruit. In case of FC-PF2.7, total ET during the irrigation period were 1005.2mm for red pepper, and 429.6mm for cucumber, respectively. 2.soil moisture extraction patterns. Average soil moisture extraction patterns (SMEP)during the irrigation period were from 1st soil layer 43% : 32% : 16% : 9% for red pepper and 39% : 34% : 15% : 12% for cucumber, respectively. The extraction ratio of the upper soils showed very large values during the early stage of growth and decreased largely during the middle stage, and became larger in the last stage. 3.The project water requirement. Among the reference crop evapotranspiration(ETo) computation methods presented by FAO, the Penman method was found to be the best. The effective rainfall was computed by a modified USDA-SCS curve number equation. Availability ratios of the total rainfall during irrigation season were 59.2% for red pepper and 48.9% for cucumber, respectively. Net project water requirement of design year are 837.3mm for red pepper. and 502.Smm for cucumber, respectively.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.1
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• pp.64-72
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• 1997

An experiment study was performed to investigate the optimum cycle of an inverter heat pump as a function of frequency. The performance of the inverter heat pump with the rated cooling capacity of 4141W(3550kcal/h) was measured with a variation of frequency, indoor and outdoor temperature, and length of capillary tube in the psychrometric test room. As a base case, the inverter heat pump with the standard capillary length of 1000mm which was optimum size for the frequency of 60Hz and ARHRAE Test condition A was tested by varying frequency from 30Hz to 80Hz. Then, the optimum cycle was invesigated by varying the length of capillary tube at each frequency levels of 30, 60 and 80Hz. Based on the experimental data, the change of system characteristics between the optimum and the base case were analyzed for each selected frequency levels. Generally, for low frequency level(30Hz), the longer length of the capillary tube compared with the standard size showed the higher EER, while for high frequency level(80Hz) the shorter length of the capillary tube showed the higher EER.

• Journal of the Korean Society of Systems Engineering
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• v.12 no.2
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• pp.47-57
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• 2016

As the inventory costs of repairable items in military logistics continue to increase, many studies for optimal inventory level of these items are being carried out in advanced countries, including the US, to reduce these costs. Research on inventory level optimization for repairable items aimed to achieve the availability goal of a system with a MIME(Multi Indenture Multi Echelon) repair policy structure first began with Sherbrooke's METRIC and developed into various types. This research is to analyze and compare recent V-METRIC related studies to search for another variation in this field. This paper mainly looks at how to determine optimum inventory level for each repairable item to achieve a specific availability target within a limited budget, and also how to minimize inventory cost while achieving its availability target by determining optimal inventory level of each repairable item.

• Journal of Information Display
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• v.13 no.4
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• pp.159-166
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• 2012

In this paper, a display's emotional image quality can be primarily determined by designing the proper luminance level. Though displays with high luminance are preferred, too much light emission from a display may cause glare or visual fatigue to viewers. To find out the proper luminance level based on various video contents, this study was conducted with an OLED display with a real-black level and a wide color gamut, and with an LCD display with a high luminance level, to set the glare threshold under various conditions. The optimum luminance levels according to the display's loading ratio were found, and the maximum luminance that did not cause a glare in the test is proposed.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.5
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• pp.285-295
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• 2004

The outage cost assessment has an important position for determination of the optimal level or optimal range of reliability for power system expansion planning. Establishing the worth of service reliability is a very difficult and subjective task. While the utility cost(reliability cost) will generally increase as consumers are provided with higher reliability, the consumer costs(reliability worth) associated with supply interruptions will decrease as the reliability increases. The total costs to society are the sum of these two individual costs and the optimum or target level of reliability is achieved at minimum point of the total cost curve. This paper addresses the role, need and assessment algorithms and methodologies of the outage cost in power system expansion planning. In a case study, the outage cost has been assessed using macro approach for our country 15years(1986-200l) in the case study. Additionally, determination processing of optimum reliability level is presented in another case study with the five buses MRBTS.