• The Journal of Information Systems
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• v.17 no.4
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• pp.281-299
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• 2008

An online game is popular topic due to the increased total online game market volume nowadays. Even though many studies on an online game are released, most studies have used survey method that reveal only section of the situation like a snapshot. For this reason, previous studies have a little limitation that does not show dynamically changing issues like a product life cycle and change in customer's satisfaction. Because of this, we researched on an online game with the system dynamic model which can show dynamic simulation to analysis time series data. We chose MMORPG (Massively Multi-play Online Role Playing Game) in sort of an online game because it has many absorbing factors and enthusiastic users. We assumed that the game developer is ready for updated version game and release that periodically and focused on dormant users who used to be enthusiastic about MMORPG and designed simulation model which analyze how to influence of update and CRM strategy on users. The simulation results showed that the update has positive influences to gather new users and hold established users and CRM strategies help to prevent dormant users from transferring to rivals to offer them re-absorbing factors. Through this study, we confirmed importance of update on a online game and suggested the necessity to introduce CRM strategy in an online game market.

• Nuclear Engineering and Technology
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• v.40 no.7
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• pp.561-570
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• 2008

When reactivity insertion such as refueling occurs in CANDU reactors, the power and the water levels are tilted in the upper outer zone of the LZCS (Liquid Zone Control System) and fluctuate unstably for a certain period of time (1-5 days). The instability described above is observed in most CANDU reactors in service around the world, but its root cause is unidentified and no solutions to this problem have been established. Therefore, this study attempted to prove experimentally and analytically that the root cause lies in the hold-up of light water on the top of the TSP (Tube Support Plate) due to the mismatch between net volumetric flow rate of light water and helium crossing the narrowed porous TSP installed within the LZCS compartment. Our method was to perform a hydrodynamic simulation of in/outflow of light water and helium. Two solutions for the aforementioned instability of LZCS are suggested. One is to regulate the compartment for both inflowing helium gas and outflowing light water; the other is to enlarge the flow paths of helium and light water within TSP. The former may be applicable to nuclear reactors in service and the latter to those planned for construction.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.76-81
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• 2009

A novel design method of time-interleaved subranging ADC is presented. We use the bisection method to let only half of comparators in typical subranging ADC working in every clock cycle. Thus, we are able to reduce the number of comparators by half. It is possible to reduce the die size. An example of 8-bit time-interleaved subranging ADC operates at 40MHz sampling rate and 1.8V supply voltage is demonstrated. The power consumption of the proposed circuit is only 10mV with SPECTRE simulation. Compared with the typical subranging ADC, our bisection method is able to reduce up to 40% in die size.

• The Korean Journal of Financial Management
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• v.27 no.1
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• pp.121-156
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• 2010

Back-door-listing can be viewed both as M&A and an alternative to IPO. If IPO is an access to the capital market through regulations, back-door-listing would be the way of entering the market through trading. Back-door-listing can be a better choice considering the common wisdom that regulations hinder the functioning of free market system. One would, however, prefer IPO, for the informational asymmetry isless severe in case of IPO. This paper examines if IPO is superior to back-door-listing as to the informational efficiency. The excess buy-and-hold returns of the Kosdaq back-door-listing firms are estimated over the three-year-period since the event. They are compared against the excess buy-and-hold returns of the Kosdaq IPO firms over the same period of time. The results confirm this paper's prediction that IPO should be more information-efficient. Both IPO and back-door-listing firms start with high short-term excess returns and end up with long-term under-performance. However, back-door-listing firms show more significantly damaging long-term results. Furthermore, back-door-listing firms record poorer accounting results over the research period. These results imply that there exists fad at the time of both events and, in case of back-door-listing, this fad is reinforced by the possibility of window dressing.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.157-168
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• 2009

The random utility theory and the multinomial logit model (including a more recent variant--the mixed multinomial logit) derived from it have constituted a back bone for theoretical and empirical analyses of various travel demand features including mode choice. In their empirical applications, however, it is customary to specify random utilities which are linear in modal attributes such as time and cost, and in socio-economic variables. The linearity helps easy derivation of important information such as value of travel time savings by calculating marginal rate of substitution between time and cost. In this paper the author focuses on the very linearity of the random utilities. Taking into account the fact that the mode chooser is also labour supplier, commodity consumer as well as leisure-seeker, the author sets up a maximization model of the traveller, which encompasses various economic activities of the traveller. The author derive from the model the indifference curve defined on the space of modal attributes, time and cost and investigate under what conditions the random utility of the traveller becomes linear. It turns out that there exist the conditions under which the random utility is really linear in modal attributes, but the property does not hold when the traveller has a corner solution on the space of modal attributes, or when the primary utility function of the traveller is directly affected by labour provided and/or the travel time itself. As a corollary of the analysis, a random utility is suggested, approximated up to the second order of the variables involved for empirical studies of the field.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.2
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• pp.414-429
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• 1997

This study aides at investigating the chang of habit in 'the Korean Catholic Womens's Religious Society' and analyzing its characteristics during the period from 1888 up to now. The research was carried out by investigating a wide range of documents including those on museums of religious society, and by considering the questionnaires and interviews on the present habit. The religious habit changed as a result of the social, cultural, and religious influence of period. The characteristics of their habit are analyzed in terms of four differnt periods as follow; (1) From the arrival of 'the Congregation of Sistersof 57 Paul de Chartres' to the year of Korean Endependence. (1888-1945) : The western style religious habit was introduced and settled later in korea by the members of forign religious society. The design of this religious halite might be originated from the mediaval times. (2) From the year of Korean Independence througt before the Vatican Council ll (1946 -1965) : Traditional habit style had been slowly modified. In this periord, ancient style coexisted with the reformed style. Also ordinary clothing style were observed in the religious society. (3) After the Vatican Council II(after 1965) : 'Decree on the up-to-date renewal of religious life'of the Vatican Council II affected strongly the traditional habile design. This led to a change from the ancient habit design to practical, modern and hygienic one. In addition, the habit was suited to the time and place as well as to the need of the apostolate. (4) Currently Situation(1996) : Mostly religious habit of korea is maintaining the style changed after the Vatican Council II. Present style is very simplyfied than the traditional one. But many religious societies make efforts for keeping the symbolic meaning of religious habit. All over the world, religious societies allowing ordinary clothes, but most korean women's religious societies still hold on religious habit.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.4
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• pp.884-892
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• 2005

Seeing through the reference of literatures ${\ll}$Internal Classic${\gg}$, ${\ll}$Donguibogam${\gg}$ and Master Jisan's theory about Ki-Hyul and Hyul-Ki, the writer came to conclusions as follows. In ${\ll}$Internal Classic${\gg}$ Ki-Hyul is expressed into being orderly and ordinate, but Hyul-Ki is described differently into making Hyul-Ki or operating Hyul-Ki. In ${\ll}$Donguibogam${\gg}$ Ki-Hyul and Hyul-Ki are not distinguished between two things, but Ki-Hyul is mentioned as harmony of Ki-Hyul and Hyul-Ki, and Hyul-Ki as ascending and descending or as deficiency and excess. In Hyungsang medicine the special characters of Ki-Hyul is seized the essence of the meanings from the deflection between left and right, changes of skin, flesh, meridian, muscle and bones. And the distinctive marks of Hyul-Ki is got hold from changes of complexion, many or few hairs, ascending or descending spirits of ears, eyes, mouth and nose. Also Ki-Hyul is recognized by laying stress on rise and fall, after birth, breast, upper limbs, eight extra meridians. And Hyul-Ki is recognized by laying stress on going up and down, the inborn constitution, abdomen, lower limbs, and twelve meridians. Jisan distinguished Ki-Hyul from Hyul-Ki theoretically and he applied the theory to clinical examination proved the facts that the theory and the examination are in accord with each other. This attempts was for the first time in Oriental medicine history and the theory was set up. It is thought that the defects of the theory about Ki-Hyul and Hyul-Ki which Jisan insisted on need much more study from now on.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.941-947
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• 2018

Station transfers for smart card based railway networks refer to transfer pedestrian movements that occur at the origin and destination nodes rather than at a middle station. To calculate the optimum path for the railway network, a penalty for transfer pedestrian movement must be included in addition to the cost of within-car transit time. However, the existing link label-based path searching method is constructed so that the station transfer penalty between two links is detected. As such, station transfer penalties that appear at the origin and destination stations are not adequately reflected, limiting the effectiveness of the model. A ghost node may be introduced to expand the network, to make up for the station transfer penalty, but has a pitfall in that the link label-based path algorithm will not hold up effectively. This research proposes an optimal path search algorithm to reflect station transfer penalties without resorting to enlargement of the existing network. To achieve this, a method for applying a directline transfer penalty by comparing Ticket Gate ID and the line of the link is proposed.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.645-649
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• 2007

Ground systems flow fault currents into the ground, and suppress Ground Potential Rise (GPR) by the current. In this paper, we designed and fabricated a surge impedance meter to analyze the ground impedance in wide frequency ranges. The meter consists of a surge generator, a high speed sample/hold (S/H) circuit and an associated electronics. The surge generator produces surge voltage up to 5kV in ranges of $50\sim500ns$. Field tests were carried out to evaluate the surge impedance meter at a driven-rod ground system. The results showed that surge impedance of ground systems should be measured by various fast surge waveforms, since the impedance increases as the rise time of applied voltage increases.

• Journal of the Korean School Mathematics Society
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• v.17 no.3
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• pp.337-358
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• 2014

The purpose of this study is to investigate how storytelling is embodied in the Mathematics I textbooks for first grade high school students in the 2009 revised curriculum and the perception of secondary math teachers and students of those books. Furthermore, in order to have some implications on newly ongoing textbook development, this thesis sets up the following goals for inquiry into the effect on storytelling. First, are there any noticeable differences among the 10 types of mathematics I textbooks for high school first graders in the 2009 revised curriculum? Second, what do teachers and students think of textbooks which apply storytelling techniques? The results are as follows. The frequency of storytelling types that appeared in the textbooks is as follows: real-life connection type and inter-scholarship type take up 47.55% and 24.51% respectively, followed by decision-making type with 10.52%, math history type with 10.17% and tool-using type with 7.05%. Within the contents, math history type showed up on reading material from every textbook. And it is worth considering that real-life-connection type has the most various topics and is mainly for arousing interest and checking up on some concepts. However, inter-scholarship type is usually related to science, and decision-making type is included for error analysis and tool-using type for reading materials about math programs. The results of this study suggest that many of the teachers who participated showed some kind of understanding of storytelling but there were not many who are actually incorporating that into their own classes. It is also essential that we develop textbooks that are effective for storytelling classes, hold regular symposiums as well as teacher training, and create tools for proper assessment. Furthermore, students think that textbooks based on storytelling would have positive effects as long as they are supported by enough time, a sufficient number of classes and tests with validity.