• Korean Journal of Poultry Science
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• v.23 no.1
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• pp.27-37
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• 1996

This experiment was carried out to study the effects of feeding split diets for a.m. and p.m. on laying hen performance and feed cost with 480 ISA Brown layers for three periods during 32∼36, 52∼56 and 72∼76 wk of age, respectively. The control group(C) was fed a conventional single diet throughout the day and split diet groups (T$_1$, T$_2$, T$_3$, T$_4$ and T$\_$5/) were offered high energy-high protein-low Ca diets, and low energy-low protein-high Ca diets in a.m. and p.m., respectively. In split diet groups, feed intake, ME and CP consumption, and feed cost were significantly reduced(P<0.05) compared to the C, while the hen-day egg production was significantly improved. However, the average egg weight was not influenced by the feeding system. Due to the reduced daily feed, ME, and CP intakes, and the improved egg production, the conversions of feed, ME, CP, and feed cost required per kg egg mass were also significantly improved (P<0.05) in splits diet groups. Among split diet groups, the T$_2$ group fed the diet devoid of Ca supplement from the conventional laying hen diet in a.m., and the diet containing the Ca supplement 2 times the conventional diet in p.m., was superior in conversion of nutrients and feed cost per kg egg mass to the other split diet groups. It was concluded that daily feed and nutrients cousumption and daily feed cost could be reduced 5∼6％ while hen-day egg production could be improved about 4％, so that about 10％ of the feed and nutrients and feed cost per kg egg mass could be spared by introducing the split diet feeding for a.m. and p.m. based on T$_2$ treatment in laying hens.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.4
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• pp.154-168
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• 2021

COVID-19 has been spreading all around the world, and threatening global health. In this situation, identifying and isolating infected individuals rapidly has been one of the most important measures to contain the epidemic. However, the standard diagnosis procedure with RT-PCR (Reverse Transcriptase Polymerase Chain Reaction) is costly and time-consuming. For this reason, pooled testing for COVID-19 has been proposed from the early stage of the COVID-19 pandemic to reduce the cost and time of identifying the COVID-19 infection. For pooled testing, how many samples are tested in group is the most significant factor to the performance of the test system. When the arrivals of test requirements and the test time are stochastic, batch-service queueing models have been utilized for the analysis of pooled-testing systems. However, most of them do not consider the false-negative test results of pooled testing in their performance analysis. For the COVID-19 RT-PCR test, there is a small but certain possibility of false-negative test results, and the group-test size affects not only the time and cost of pooled testing, but also the false-negative rate of pooled testing, which is a significant concern to public health authorities. In this study, we analyze the performance of COVID-19 pooled-testing systems with false-negative test results. To do this, we first formulate the COVID-19 pooled-testing systems with false negatives as a batch-service queuing model, and then obtain the performance measures such as the expected number of test requirements in the system, the expected number of RP-PCR tests for a test sample, the false-negative group-test rate, and the total cost per unit time, using the queueing analysis. We also present a numerical example to demonstrate the applicability of our analysis, and draw a couple of implications for COVID-19 pooled testing.

• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.461-471
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• 2015

Recently, the estimation of the social cost of energy sources has been emphasized as various novel energy options become feasible in addition to conventional ones. In particular, the social cost of introducing measures to protect power-distribution systems from power-source instability and the cost of accident-risk response for various power sources must be investigated. To account for these risk factors, an integrated societal risk assessment framework, based on power-uncertainty analysis and accident-consequence analysis, is proposed. In this study, we applied the proposed framework to nuclear power plants, solar photovoltaic systems, and wind-turbine generators. The required capacity of gas-turbine power plants to be used as backup power facilities to compensate for fluctuations in the power output from the main power source was estimated based on the performance indicators of each power source. The average individual health risk per terawatt-hours (TWh) of electricity produced by each power source was quantitatively estimated by assessing accident frequency and the consequences of specific accident scenarios based on the probabilistic risk assessment methodology. This study is expected to provide insight into integrated societal risk analysis, and can be used to estimate the social cost of various power sources.

• Journal of the Korea Society for Simulation
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• v.10 no.1
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• pp.35-50
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• 2001

Managing multi-echelon inventory systems has gained importance over the last decade mainly because integrated control of supply chains consisting of several processing and distribution stages has become feasible through modern information technology. Determination of optimal inventory policy for multi-echelon supply chain is made difficult by the complex interaction between the different levels. In this paper, we investigate performance of five inventory policies (fixed quantity order policy, fixed interval order policy, compromised order policy, lead time-fixed quantity order policy, and mixed order policy) in a multi-echelon supply chain by using a simulation model constructed with AweSim simulation language. The results of the simulation study show that the mixed order policy is the best among five inventory policies in the most test problems except the case when the stockout cost per unit is much higher than the inventory holding and transportation costs per unit.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.1
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• pp.1-9
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• 2022

Fixslicing AES is a technique that omits the Shiftrows step to minimize the cost of the linear layer of Bitsliced AES, showing a 30% performance over the Bitsliced technique. However, the amount of code increases to compensate for the omitted shiftrows. Therefore, it is proposed to be divided into Semi-Fixsliced in which only half of shiftrows are omitted and Fully-Fixsliced in which Shiftrows are omitted completely. In this paper, we propose a CTR mode implementation of Fixslicing AES on RISC-V using the pre-computed table technique. By utilizing the characteristics of the CTR mode, it is possible to perform fast encryption by omitting up to the second round SubBytes from the encryption process through pre-computed up to the second round SubBytes operation. Using this technique, it was confirmed that Semi-Fixsliced has a performance of 1,345 cycles per block and a performance improvement of 7% compared to the previous performance result, and Fully-Fixsliced has a performance of 1,283 cycles per block and a performance of 9% compared to the previous performance result on 32-bit RISC-V.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.7 no.1
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• pp.10-16
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• 2011

Performance of ground-source heat pumps (GSHPs) is mainly affected by ground heat exchangers which makes up more than 40% of construction cost. Exact construction and grout as backfill are important, because it is difficult to repair after being installed. As grout materials, bentonite grout material and cement material are used In this paper, thermal conductivity according to mix proportion of cement grout has been experimentally studied. Some variables were set to evaluate thermal conductivities according to change in cement content, unit water ratio, mass per volume of fresh mortar, and aggregate types. From the experimental analysis, high performance cement grout has been proposed.

• The Transactions of the Korea Information Processing Society
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• v.7 no.7
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• pp.2196-2203
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• 2000

As processor's operational frequency increases and processors execute multiple instructions per cycle, the processor performance becomes more dependent on the load operand referencing latency and the data dependency. To reduce the operand fetch latency and to increase ILP by breaking the data dependency, we propose a value-address hybrid predictor using a reasonable size prediction buffer and analyse the performance improvement by the proposed predictor. Through the extensive simulation of 5 benchmark programs, the proposed hybrid prediction scheme accurately predicts 62.72% of all loads which are 12.64% higher than the value prediction scheme and show its cost-effectiveness compared to the address predition scheme. In addition, we analyse the performance improvement achieved by the stride management and the history of previous predictions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.58-59
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• 2014

EVM(Earned Value Management) is a management methodology for integrating scope, schedule and resources, and for objectively measuring project performance and progress. EVMS(Earned Value Management System) has been used for the performance measurement of R&D and construction projects in developed countries such as United States, United Kingdom and Australia. The nuclear power plant (NPP) projects in Korea have not applied EVMS. However, EVMS has come into request for overall schedule and cost risk management and performance measurement in overseas project of the nuclear power plant as a contractor. In this paper, based on the global EVMS guidelines, EVMS per unit processes have been developed for NPP projects. Moreover, using Business Process Management (BPM), it proposes an integrated process model with tasks, roles, and procedures for EVMS for NPP construction projects.

• ETRI Journal
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• v.37 no.4
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• pp.685-695
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• 2015

This paper proposes a novel video delivery scheme that reduces the bandwidth consumption cost from a video server to terminals in Long-Term Evolution networks. This proposed scheme combines optimized hybrid multicast with a segment-based caching strategy for use in environments where the maximum number of multicast channels is limited. The optimized hybrid multicast, allocation of multicast channels, and cache allocation are determined on the basis of a video's request rate, the related video's length, and the variable cost per unit size of a segment belonging to the related video. Performance evaluation results show that the proposed scheme reduces a video's delivery costs. This work is applicable to on-demand TV services that feature asynchronous video content requests.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.321-332
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• 2015

In an attempt to find the improvement of the fishing efficiency according to the hull form remodeling for the 3 tuna purse seiner, the Catch-Per-Unit-Effort (CPUE) for that undertaken before (2008) and after (2010) was analyzed. In addition, the CPUE of 6 similar ships operated same period and same fishing ground. As result, it came to verify that the three modified ships had a significant value on the CPUE. An another index for the improvement of fishing efficiency is the rate of reduction of fuel oil consumption for the modified ships. Fuel oil consumption per day in service speed as comparing with the original ships were reduced 2.1%, 4.0% and 5.1% on the modified ship A, B, and C respectively. And each ship's service speed was increased 1.0 kt, 0.6 kt, and 0.4 kt according to the modified ship A, B, and C in due order. In the conclusion, the remodeling job with newly equipped bulbous bow, lengthened slipway and enlarged rudder area were improved fairly much on fuel oil efficiency, the ship's speed, and in the end, that led to the improving fishing efficiency. Hence, the remodeling of tuna purse seiner come to improve not only the fishing performance, but contribute to the reduction of operating cost by saving energy for the fisheries industry.