• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.75-86
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• 2011

This paper describes several current research activities and the field techniques for the prevention of human errors during the operation of nuclear power plants(NPPs). The human aspects such as 'fitness for the duties', 'job competence and suitability', 'types of communication', 'behaviors of field workers', 'teamwork of main control room crews', 'task procedures', etc. have been investigated for improving the performance of operating personnel in NPPs. We decide to develop a set of the complementary techniques for the reduction of human errors. The set of techniques developed includes teamwork criteria, jobs fitness analysis, procedure enhancement guide, 3-way communication, campaign posters, a behavior based safety program, a procedure guideline, and a task hazard identification method for the field practitioners in NPPs. These can offer a set of significant human error countermeasures to be considered for analyzing and reducing human error in NPPs as well as other fields of industry.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.2
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• pp.453-461
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• 2010

This paper presents a branch prediction algorithm and a 4-way set-associative cache for performance improvement of embedded RISC core and a clock-gating algorithm using ODC (Observability Don't Care) operation to improve the power consumption of the core. The branch prediction algorithm has a structure using BTB(Branch Target Buffer) and 4-way set associative cache has lower miss rate than direct-mapped cache. Pseudo-LRU Policy, which is one of the Line Replacement Policies, is used for decreasing the number of bits that store LRU value. The clock gating algorithm reduces dynamic power consumption. As a result of estimation of performance and dynamic power, the performance of the OpenRISC core applied the proposed architecture is improved about 29% and dynamic power of the core using Chartered $0.18{\mu}m$ technology library is reduced by 16%.

• Journal of IKEEE
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• v.23 no.3
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• pp.785-792
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• 2019

In parallel operation of multiple power converter modules, equal power distribution among modules shall be made to improve the reliability of the system. In this paper, a novel droop method is proposed to present improved current distribution characteristics. In the proposed method, if the current in each module become greater than the current set-point value, the output voltage set-point is raised to improve the current distribution characteristics. Meanwhile, when the output voltage is to be managed within the tolerance range, the range of the usable control IC reference value ($v_{ref}$) will be reduced if the output voltage setting is always raised. Thus, in case the output voltage set-point among modules is reversed, the downward adjustment is introduced. The proposed method was experimentally validated with a 17.5V/500mA prototype of two boost converters operating in parallel.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.4
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• pp.11-20
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• 2022

Currently, the operation rule of agricultural reservoirs in case of drought events follows the drought forecast warning standard of agricultural water supply. However, it is difficult to preemptively manage drought in individual reservoirs because drought forecasting standards are set according to average reservoir storage ratio such as 70%, 60%, 50%, and 40%. The equal standards based on average water level across the country could not reflect the actual drought situation in the region. In this study, we proposed the improvement of drought operation rule for agricultural reservoirs based on the percentile approach using past water level of each reservoir. The percentile approach is applied to monitor drought conditions and determine drought criteria in the U.S. Drought Monitoring (USDM). We applied the drought operation rule to reservoir storage rate in extreme 2017 spring drought year, the one of the most climatologically driest spring seasons over the 1961-2021 period of record. We counted frequency of each drought criteria which are existing and developed operation rules to compare drought operation rule determining the actual drought conditions during 2016-2017. As a result of comparing the current standard and the percentile standard with SPI6, the percentile standard showed severe-level when SPI6 showed severe drought condition, but the current standard fell short of the results. Results can be used to improve the drought operation criteria of drought events that better reflects the actual drought conditions in agricultural reservoirs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.3
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• pp.300-305
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• 2008

Purpose: The purpose of our study was to evaluate the volume of pre- and post operative masseter muscle and bite force in mandibular prognathic patients treated with SSRO with the use of the 3D CT imaging technique and occlusal force meter. Materials and methods: The study group consisted of 12 patients with mandibular prognathism (5 males and 7 females) who underwent mandibular setback surgery (BSSRO) in the Department of Oral and Maxillofacial Surgery, Samsung medical center. Bite force was measured at pre op, post op 3, 6 and 12 months by occlusal force meter(GM10, Nagano Keiki, Japan) The preoperative CT examination of subjects was performed between one month prior to operation and one year after to operation. And muscle volume was measured. Result: As compared to preoperative measurements at 1 year postoperatively the masseter & internal pterygoid muscle volume were diminished (p<0.05) The bite force steadily recovered, so at postoperatively 6 months reached the preoperative level. And at 1 year after operation, the maximum bite force was significantly greater than preoperative levels. No significant correlation was presented between masseter muscle and bite force (p>0.05), internal pterygoid muscle and bite force (p>0.05). Conclusion: In this study, the results showed that volume and bite force of the masticatory muscles decreased significantly immediate after orthognathic surgery for mandibular set-back. However, reduction of maximum bite force disappears within 6 months after surgery.

• Membrane and Water Treatment
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• v.9 no.6
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• pp.421-434
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• 2018

Decision-makers have different and sometimes conflicting goals with utilities in operating dam reservoirs. As repeated interactions exist between decision-makers in the long-term, and the utility of each decision-making organization is affected not only by its selected strategy, but also by other rivals' strategies; selecting and prioritizing optimum strategies from a decision maker's point of view are of great importance while interacting with others. In this paper, a model based on a fuzzy set theory, for determining the priority of decision-makers' strategies in optimal qualitative-quantitative operation management of dam reservoir is presented. The fuzzy priority matrix is developed via defining membership functions of a fuzzy set for each decision maker's strategies, so that all uncertainties are taken into account. This matrix includes priorities assigned to possible combination for other decision makers' strategies in bargaining with each player's viewpoint. Here, the 15-Khordad Dam located in the central part of Iran, suffering from low water quality, was studied in order to evaluate the effectiveness of the model. Then, the range of quality of water withdrawal agreed by all decision-makers was determined using the prioritization matrix based on fuzzy logic. The results showed that the model proposed in the study had high effectiveness model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.4
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• pp.371-377
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• 2013

Fishing boats more than 5 tons is obliged to VHF DSC by Fishing Vessels Act and Vessel Safety Act. The owner of the fishing vessel is equipped to the automatic position reporting device in accordance with the Notice of the Minister of Land, Transport and Maritime Affairs to regulations, shall be ensure to navigations safety and in order to respond quickly in the event of maritime accidents on fishing vessels. East sea set up to start in 2012, which is now underway the annual install plain to the yellow sea and the south sea for VHF coast stations. It is web-based remote operation of DSC on the remote control and monitoring in Fishery Information Communication Station for the coastal VMS construction project. All fishing vessels is VHF DSC in conjunction with the GPS that location information transmitted to the coast station. automatically by the DSC call. This paper has been studied on the communications coverage set up and traffic operation for realization a roaming service by navigation route tracking and RSSI techniques in parallel algorithm refer to VHF DSC coast stations in east sea.

• Journal of Life Science
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• v.18 no.9
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• pp.1284-1289
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• 2008

This research was conducted to elucidate the optimum conditions for the maesil vinegar fermentation by Acetobacter sp. SK-7 using evolutionary operation (EVOP)-factorial design technique. The acidity of maesil vinegar was effected by ethanol concentration in the range of 3-7% (r=-0.5166), and glucose concentration in the range of 0.1-0.5% (r=-0.5061). The acidity of maesil vinegar was not effected by differentiation of temperature in the range of 24-$33^{\circ}C$ (r=0.1082). The optimum maesil vinegar fermentation by Acetobacter sp. SK-7 as determined by the EVOP-factorial design technique was obtained at an fermentation temperature of $30^{\circ}C$, ethanol concentration of 4%, glucose concentration of 0.2%. Furthermore, the acidity of vinegar increase from an initial acidity of 5.4% to 6.365% in the third set that is nearly 1.0% by EVOP-factorial design technique

• School Mathematics
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• v.13 no.3
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• pp.405-422
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• 2011

In this study, we consider the meaning of one-to-one correspondence through theoretical background under operation of matrix. On algebraic point of view, its significance is 'through one-to-one correspondence from a set with given structure, become a methods in order to induce an algebraic system in to a new set.' That is a key idea making isomorphic structure. Such process experiences necessity of mathematical fact, as well as the deep understanding of one-to-one correspon -dence. Also that becomes a base for develop a various mathematical concepts, such as matrix, exponential laws, symmetric difference, permutation and so on. This study help teachers and students to understand of mathematical concepts meaningfully and to facilitate teacher's professional development.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.202-216
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• 2020

In this study, we studied the utility and value of the mileage program as a strategy to strengthen the relationship with customers in the surrogate operation industry. To this end, we conducted a survey of 1,000 customers who used the service more than once, mainly from D company, which has operated the agency operation business for more than 20 years, and analyzed 309 sincerely respondents. Five characteristics of mileage use (emotional benefits, ease of use, economic usefulness, effort to acquire, variety of benefits). Two parameters (brand attitude, brand loyalty) were set, and the dependent variable was set for reuse. As a result of hypothesis test, emotional benefit, convenience of use, and economic usefulness were significant in terms of brand attitude and brand loyalty, and acquisition effort and benefit diversity did not show significant results. The results of this study showed that the surrogate operation industry should strive to strengthen the emotional benefits, convenience of use, and economic usefulness to customers in order to strengthen the relationship with the customers.