• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1810-1817
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• 2015

The railway vehicle has an auxiliary power unit for supplying power to the associated electronic control devices and passenger service unit. Typically, input voltage from the catenary for rolling stock is highly fluctuating according to the substation capacity, vehicle propulsion and regeneration. Especially, the frost and freezing on contact wire in winter can cause a blackout inside vehicle, and also brings about electronic components damaging and the system down. To prevent this problem, a large filter and capacitor is used. But this is not a perfect solution, because it is increasing weight of the unit. In this paper, a new algorithm is proposed to suppress the disturbance without adding devices. Simulation and experimental results show that the proposed algorithm has performance to suppress the disturbance at the sudden input voltage variations.

• School Mathematics
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• v.11 no.2
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• pp.243-260
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• 2009

In this paper, we have designed a teaching unit for the learning mathematising of secondary pre-service teachers by exploring generalized fibonacci sequences. First, we have found useful formulas for general terms of generalized fibonacci sequences which are expressed as combinatoric notations. Second, by using these formulas and CAS graphing calculator, we can help secondary pre-service teachers to conjecture and discuss the limit of the sequence given by the rations of two adjacent terms of an m-step fibonacci sequence. These processes can remind secondary pre-service teachers of a series of some mathematical principles.

• Korean Institute of Interior Design Journal
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• v.16 no.3 s.62
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• pp.93-101
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• 2007

The purpose of this study is to propose our direction of long-tenn care facility for elderly. The long-tenn care insurance plays an important role for human well-being. The functional and architectural changes of Japanese elderly care facilities have been analysed in order to predict changes in Korean welfare facilities. In Japan, Unit-care and private rooms are essential elements after reforming welfare facilities for aged. This study proposes components of unit-care through the analysis of 20 facilities for the aged. A unit is basically consist of private rooms, rest room, public living area, kitchen, health care service station, and bath room. Besides, smoking room, tea room, public terrace, guest room, court yard, and so on can be added. A unit can be connected with other unit by semi-public spaces or can be independently organized. This relationship has been classified into 2 types; Open unit type and Separated unit type.

• The Korean Journal of Emergency Medical Services
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• v.6 no.1
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• pp.77-86
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• 2002

The purposes of this research which was conducted by surveying lost/added unit hours reports, unit hour demand analysis worksheets from prehospital care reports of two squads in Kyonggi Provincial Fire and Disaster Headquarters for 20 weeks (January 1, 2002 - May 20, 2002) are to get Unit Hour Utilizations. Call Demands such as Unit Hour Demand, Simple Average Demand, High Average Demand, Peak Average Demand, the High Actual Demand. The conclusions from this analysis were summarized as follows: (1) By revealing Unit Hour Produced 3223.9, Call Volume 964, Unit Hour Utilization 0.299 at the Squad A and Unit Hour Produced 3328.4, Call Volume 901, Unit Hour Utilization 0.271 at the Squad B induced Korean Squads to chance identification, definition, direction of Unit Hour Utilization. (2) By revealing Simple Average Demand 7.4 on Monday Tuesday, High Average Demand 9.6 on Tuesday Friday. Peak Average Demand 11.5 on Tuesday, the High Actual Demand 12 on Tuesday Wednesday at the Squad A and Simple Average Demand 6.8 on Sunday, High Average Demand 10.4 on Monday, Peak Average Demand 11.5 on Monday, the High Actual Demand 13 on Monday at the Squad B enabled Korean Squads to utilize System Status Management. (3) The Maximum Calls per Unit Hour were 115 for 23:00~23:59, the Minimum Calls per Unit Hour were 46 for 05:00~05:49 in two squads. The Maximum Calls per Unit Hour were 7.4 on Tuesday Saturday, the Minimum Calls per Unit Hour were 6.1 on Thursday at the Squad A. The Maximum Calls per Unit Hour were 7.3 on Monday Saturday, the Minimum Calls per Unit Hour were 5.6 on Thursday at the Squad B. (4) Analyzing demand for EMTs in the optimum emergency medical service of Korea, we have been able to utilize this Unit Hour Utilization in company with the established estimation methods such as international comparisons or the number of ambulances for scientific reasonable estimation. (5) These Call Demands which were limited to the demand time in this study will make us expect some following studies including demand time, demand time, demand map for Strategic Deployment.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.151-156
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• 2000

The brake system is important to stop train safely. The train is sloped by regenerative brake and pneumatic brake which are continuously blended at service brake. When service is applied to train, it is controlled by train weight and brake command. The jerk limitation function is applied for impulseless smoothing braking. All brake applications in service condition have a function of the variable load control to keep the braking effort in proportion to each car load. All of control function are performed by brake controller. Therefore, we will propose the design of brake control system in order to control efficiently

• Spatial Information Research
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• v.15 no.3
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• pp.203-218
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• 2007

The purpose of this article is to set up the scientific and reasonable norm of location and service area determination instead of the pro-administrative lacking availability, so as to propose more practical and reasonable standard of space unit for the location of facilities. This article has accepted the method of Voronoi Diagram as a new scientific and reasonable criteria. The article chooses and realizes a model that can propose a new service area, transform and apply to improve its reality, and assesses which has more reality and compatibility by comparing the models. The result from this procedure can be adapted in objectification of the service area determination and formation of the standard space unit.

• Journal of Distribution Science
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• v.14 no.3
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• pp.73-83
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• 2016

Purpose - The parcel delivery service(courier) industry all over the world has been expanding its market so far, but its growth has been declining in recent years. In this situation, most parcel delivery companies are having trouble with managing themselves because of the pressure from the customer to increase service level and decrease the rate. The purpose of this study is to provide ways to improve competitive advantages of the parcel delivery service industry by evaluating the multi-period operating efficiency of Korea, Japan and global service providers. Research design, data, and methodology - The data for the period of 2011 to 2014 were collected from the annual reports published by parcel delivery companies. In this study, we analyze the marketability (revenue), profitability (operating profits), and management conditions (net profits) of parcel service companies by combining information on human resources (number of employees) and material resources (total assets and equity). Therefore, the number of employees, total assets, and equity are selected as input variables, and revenue, operating profits, and net profits as the output variables. In this study, DEA (Data Envelopment Analysis) is used to measure the comparative efficiency and MPI (Malmquist Productivity Index) is used to analyze the trend of change of the efficiency for a multi-year period. Results - The operational efficiency scores of medium-sized parcel delivery companies in Korea are higher than other larger competitors such as Korean, Japan and Global larger companies. As of 2014, Logen(1.878) was found to be the most efficient parcel delivery enterprise, followed by KGB (1.224), and Kyoungdong(1.002). Otherwise, Hanjin(0.235), CJ(0.262), Hyundai Logistics(0.657), DHL(0.611), UPS(0.766), FedEx(0.498), TNT(0.350), Yamato(0.762) and Sagawa(0.520), larger sized companies, were done inefficiently. The productivity of parcel delivery companies is influenced by endogenous factors as well as exogenous ones such as changes in business environment and technological advances. Conclusions - Korean medium-sized companies have relatively high efficiency scores in operation. That is why they still survive the competitive market in Korea where market restructuring on the industry has been expected to be conducted for many years. The reason why medium-sized couriers had higher efficient scores than larger couriers is that most of couriers spend more operating expenses versus unit price of delivery which is the amount of money that is needed in order to send a package by parcel service. So the delivery unit price must be taken into account by all the expenses associated with the cost of fuel, labor and maintenance expenses for facilities, etc. therefore, the unit price must be increased to strengthen business competitive power. In order for the industry to have more competitive advantage, the companies need to make profits by increasing demand volume and raising the delivery rate to provide high-quality delivery service to customers. And both endogenous and exogenous change must take precedence in order to strengthen their competitiveness.

• Journal of Educational Research in Mathematics
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• v.13 no.1
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• pp.57-75
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• 2003

The goal of this paper is to offer material which make mathematising Fruedenthal(1991) proposed be experienced through the process of teaching and learning mathematics. In this paper, the number of unit squares a diagonal passes through for an m$\times$n lattice rectangle is studied and its generalization is discussed. Through this discussion, the adaptability of this material Is analysed. Especially, beyond inductional conjecture, the number of unit squares is studied by more complete way, and generalization in 3-dimension and 4-dimension are tried. In school mathematics, it is enough to generalize in 3-dimension. This material is basically appropriate for teaching and learning mathematising in math classroom. In studying the number of unit squares and unit cubes, some kinds of mathematising are accompanied. Enough time are allowed for students to study unit squares and unit cubes to make them experience mathematising really. To do so, it is desirable to give students that problem as a task, and make them challenge that problem for enough long time by their own ways. This material can be connected to advanced mathematics naturally in that it is possible to generalize this problem in n-dimension. So, it is appropriate for making in-service mathematics teachers realize them as a real material connecting school mathematics and advanced mathematics.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.11
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• pp.1807-1817
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• 2018

Objective: This study aimed at investigating white striping (WS) and wooden breast (WB) cases in breast meat collected from commercial broilers. Methods: A total of 183 breast samples were collected from male Ross 308 broilers slaughtered at the age of 6 weeks (n = 100) and 7 weeks (n = 83). The breasts were subjected to meat defect inspection, meat quality determination and histology evaluation. Results: Of 183, 4 breasts from 6-week-old broilers were classified as non-defective while the others exhibited the WS lesion. Among the 6-week-old birds, the defective samples from the medium size birds (carcass weight ${\leq}2.5kg$) showed mild to moderate WS degree with no altered meat quality. Some of the breasts from the 6-week-old birds with carcass weight above 2.5 kg exhibited WB in accompanied with the WS condition. Besides of a reduction of protein content, increases in collagen matter and pH values in the defective samples (p<0.05), no other impaired quality indices were detected within this group. All 7-week-old broilers yielded carcasses weighing above 2.5 kg and showed abnormal characteristics with progressive severity. The breasts affected with severe WS and WB showed the greatest cook loss, hardness, springiness and chewiness (p<0.05). Development of WB induced significantly increased drip loss in the samples (p<0.05). Histology indicated necrotic events in the defective myofibers. Based on logistic regression, increasing percent breast weight by one unit enhanced the chance of WS and WB development with advanced severity by 50.9% and 61.0%, respectively. Delayed slaughter age from 6 to 7 weeks increased the likelihood of obtaining increased WS severity by 56.3%. Conclusion: Cases of WS and WB defects in Southeast Asia have been revealed. Despite few cases of the severe WS and WB, such abnormal conditions significantly impaired technological properties and nutritional quality of broiler breasts.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.2
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• pp.229-237
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• 2016

The purpose of this paper is to empirically identify whether unit bias exists or not under the flat rate pricing in the Korean mobile telecommunication market and to give the desirable form of pricing plans for minimizing this irrational behaviors. Our results show that with the flat rate pricing consumers tends to make more voice or data traffic over their optimal consumption level, meaning the existence of unit bias in the Korean mobile market. These results imply that under the current pricing plans subscribers may pay higher monthly fee than their optimal cost which maximizes their utility, for using the telecommunications service. Thus, policy makers need to consider adopting mobile operators' segmentation of the flat rate pricing plans for the reduction of subscribers' telecommunications costs and the improvement of consumer welfare.