• Journal of the Korean Statistical Society
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• v.30 no.4
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• pp.661-666
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• 2001

In this paper we consider an M/G/1 queue where the server of the system has a vacation time and the service policy is limited-1. In this system, upon termination of a vacation the server returns to the queue and serves at most one message in the queue before taking another vacation. We consider two models. In the first, if the sever finds the queue empty at the end of a cacation, then the sever immediately takes another vacation. In the second model, if no message have arrived during a vacation, the sever waits for the first arrival to serve. The analysis of this system is particularly useful for a priority class polling system. We derive Laplace-Stieltjes transforms of the waiting time for both models, and compare their mean waiting times.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.4
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• pp.340-344
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• 2004

In this paper, We collected the data of communication network construction in Sangmyeong University and analyzed them. Moreover using the analysis instrument of communication network traffic, We tested a process of it, and an efficiency of each equipment. We proved the traffic flow and the load quantity during the register for class. As a result We suggested a efficient communication network design - add and change some equipments in order to break up the traffic.

• Korean Journal of Computational Design and Engineering
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• v.18 no.1
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• pp.28-35
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• 2013

Product Life cycle Management (PLM) is an indispensable tool for manufactures to develop competitive products in an efficient way. This enlarges the number of participants for product development who should understand PLM for their supporting activities. However, burdens for developing example products, maintaining complex PLM systems and training prerequisite skills for engineering tools such as CAD systems prohibit an efficient introductory course to PLM. This paper proposes a comprehensive introductory course to PLM that bases on general product development process. In addition, it enables participants to build their example products with familiar Lego blocks and to construct 3D CAD assembly models by using predefined 3D elements. The PLM system for the course provides an intuitive and simple user environment for participants to specify their parts lists, associated 3D CAD models, and product structure of example products. Experiences on a class of the course show it is a valid and efficient education and training method for the PLM introduction.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.579-584
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• 2017

SBAS is a satellite based navigation correction system that provides correction information and integrity information of GNSS signal through geostationary satellite based on analysis of GNSS signal in ground station. KASS, a Korean SBAS, is aiming at the APV-1 class SoL service in 2022. Sufficient ground and flight tests must be performed in advance to provide SoL services. However, since KASS, the Korean SBAS, has not yet been added in Korea, specific detailed evaluation items are not presented. EGNOS, which is expected to be the most compatible with KASS and is being serviced after its development, has already been evaluated. In this paper, we analyze the regulations applied to EGNOS construction and analyze the criteria of ground and flight test evaluation items required for flight testing, which is expected to be referenced to the flight inspection process in the future.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.10
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• pp.134-141
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• 2004

This paper addresses development of the conceptual design program of satellite communication system. A database for more than 200 small satellites of LEO which are between 10kg and 200kg was constructed to conduct a sequential process of conceptual design. General parameters based on the database were derived to be able to use for initial design of satellite communication system. The general conceptual design process developed and programed in this work is applicable to micro-class small satellites without regard to mission types. This conceptual design algorithm is consisted of five sequential steps, in which various parameters are defined every phase. These parameters are utilized for conceptual design through database analysis. The validity of an entire design algorithm has been demonstrated via program simulation.

• Journal of Distribution Science
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• v.4 no.2
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• pp.5-20
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• 2006

Retail is called location business because it is one of the most important factors to estimate management of stores for retailers who are going to sell products directly to customers. Retailers' management achievements are shown in sale in general. Therefore, retailers tend to focus on ways to increase the numbers of customers in order to raise sales. First of all, in this research, I am going to examine the most fundamental models such as Reilly's retail gravitation, converse model, huff probability model and multiful losit model in selecting stores. Secondly, I am going to provide the process and analyzing ways to predict estimated sales amount with the previous theory model. Also I am going to predict estimated sales amount of the department store L which is located in D metorpolitan city. Lastly, I am going to argue about the problem of this research and the next research subject. Our main goal is to provide ways to complement and inspect sales estimation models, which can be used in fields after taking characters of high class structure of Korea into consideration on the base of previous researches. According to the result of the research, my conclusion is that if the process of analysis and changing factors are complemented, revise model, which can reflect reality of Korea, will be provided. Therefore, in the future study, we have to build up theory models to suit for our retail market through critic reviews about the existing high class structure of Korea.

• International Journal of Quality Innovation
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• v.8 no.3
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• pp.123-155
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• 2007

This research treated the secondary school teachers as the research scale and the research targets included the following: secondary school (employ unit), center of teacher education, and qualified teachers. In terms of these three groups of people, the topics of exploration focused on the perception of suitable teachers, perception of evaluation standard during the process of teacher examination and the relationship among teacher examination systems. The research was managed by two phases: the first phase referred to literature reorganization, expert interview, the qualities and conditions of suitable teachers, important evaluation standard during the process of teacher examination and teacher examination system used; the second phase included questionnaire survey, employ school acquisition, the perception of centers of teacher education and qualified teachers toward the suitability condition and examination evaluation standard in the first phase and teacher examination system used. This research found out that as to the perception of suitable teachers, through data collection, there were six factors reorganized. The levels of their importance were as follows: education devotion, teaching capacity, class management, capacity to guide special students, capacity to communicate with the parents and the will to undertake administrative works. Noticeably, employee unit and centers of teacher education apparently valued class management more, compared with trained teachers; as to evaluation standard of examination, the analytical result found out that the perception of three groups were different in terms of the views toward educational works, written examination data, candidate's age, club experience at school and capacity to use multimedia support teaching materials. This research further proposed six suggestions for centers of teacher education and trained teachers: (l) employ schools considerably valued educational devotion; (2) trained teachers tended to neglect the importance of class management; (3) employee unit considerably cared about the new teachers' competence to use multimedia support teaching materials; however, trained teachers did not have the same view; (4) employee unit considerably cared about new teachers' views toward educational works as well as the candidates' ages; (5) generally speaking, trained teachers neglected the importance of club experience at school; (6) the data revealed that written examination data was not relatively important in terms of teacher examination.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.82.2-82.2
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• 2012

We present Herschel-PACS observations of L1448-MM, a Class 0 protostar with a prominent outflow, part of the DIGIT Key Program (PI: N. Evans). We detect numerous emission lines including CO and $H_2O$ rotational transitions, OH transitions, and [OI] forbidden transitions at wavelengths from 55 to 210 ${\mu}m$. The $H_2O$, [OI], mid-J CO (J < 23), and OH emission distributes along the outflow direction although high-J CO and other OH emission peaks at the central spatial pixel. According to our simple excitation analysis, CO seems to have two temperature components of warm and hot, which might be attributed to the PDR and shock, respectively. After exploring a wide range of physical conditions with a non-LTE LVG code, RADEX, we found that either shock alone or the combination of PDR and shock can explain the observations. The relative fraction of observed line luminosities suggest that L1448-MM is shielded from the UV radiation because $H_2O$ and CO are the dominant coolants rather than OH and [OI]. In addition, our observed fluxes match better with C-shock models rather than J-shocks. The non-LTE LVG model supports that the IR pumping process is important for OH transitions because the OH line ratios are fitted much better when the dust thermal continuum is included.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.7
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• pp.984-999
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• 2013

This research examines the interrelation of clothes, colors and sentiments based on clothes and colors that stimulate sentiment. This study provides data that is useful to color therapy by means of clothes as medium. The survey for this study targeted 200 Pusan National University students who analyzed the colors of association and clothes colors for nine positive vocabularies (passion, love, warmth, happiness, interest, softness, comfortable, freshness, and coolness) and six negative vocabularies (anger, fear, despair, nervous, gloomy, and loneliness). The data collection process used 120 standard colors as represented by Munsell's basic 10 colors (R, YR, Y, GY, G, BG, B, PB, P, RP) as chromatic colors classified into eleven tones of colors (V, S, B, P, VP, LGR, GR, L, DL, DP, DK) and achromatic colors divided into ten steps of brightness N1-N10. The results of the research are as follows. First, the warm class of colors were significant in the colors of association with positive sentiment and the cold class of colors were significant in the sentiment of refreshment and coolness. In addition, bright and clear colors (like V, S, VP, P) were associated with color tones. Second, the low bright achromatic colors were generally high for the colors of association with negative sentiment; in addition, the color of R, PB, P (as achromatic colors) were also significant. In addition, sober and dark tones (like GR, DL, DK, DP) were significant in color tones. Third, the interrelation between positive sentiment and clothes colors shows that colors of association were mainly used for upper garment colors. Similar colors against upper garments were used together for bottom garment achromatic colors and complementary colors; therefore, bottom garments play a subsidiary role in the concept of coordination with upper garments.

• Journal of Veterinary Clinics
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• v.8 no.1
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• pp.1-10
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• 1991

The B-lymphocyte differentiation from committed B-cell progenitors to antibody-secreting cells was discussed. B-cell progenitors derived from hematopoietic stem cells undergo the rearrangement of immunoglobulin(Ig) gene. The earliest cells as B-cell precursors have cytoplasmic Is(${\mu}$ chain). The entire Is molecule is expressed on the surface after synthesis of L chain. The resting B cells(Go stage) stimulated by binding antigen via Ig-receptors are activated(G$_1$ stage) and followed by proliferation(S stage), coupled with further selection(affinity maturation. class switch). The production of antibody against a particular antigen depends on the activation of B cells with surface Is capable of reacting with that antigen. This process does not occur in isolation but is controlled by helper and suppressor T cells and antigen presenting cells(APC). The mechanism of T cell-dependent B-cell response for production of antibody is largely explained by the cell to cell cooperation and soluble helper factors of T cells. 1) The antigen specific B cells and helper T cells are linked by Is-receptors, leading to the delivery of helper signals to the B cells. 2) Helper T cells recognize the processed antigen-derived peptides with the MHC class II molecules(la antigen) and is stimulated to secrete B-cell proliferation and differentiation factors which activate B cells of different antigenic specificity. The two models are shown currently 1) At low antigen concentration, only the antigen-specific B cell binds antigen and presents antigen-derived peptides with la molecules to helper T cells, which are stimulated to secrete cytokines(IL-4, IL-5, etc.) and 2) At high antigen concentration, antigen-derived peptides are presented by specific B cells, by B cells that endocytose the antigens, as well as by APC Cytokines secreted from helper T cells also lead to the activation of B cells and even bystander B cells in the on- vironmment and differentiate them into antibody-secreting plasma cells.