• Journal of Korea Spatial Information System Society
• /
• v.9 no.3
• /
• pp.25-33
• /
• 2007

The local governments of major cities in Korea are giving focus on public transportation to reduce congestion and improve accessibility in city areas. In this regards, the proper measurement of accessibility is now a key policy requirement for reorganizing the public transport network. Public transport routing problems, however, are considered to be highly complicated since a multi-mode travel generates different combinations of accessibility. While most of the previous research efforts on measuring transport accessibility are found at zone-levels, an alternative approach at a finer scale such as bus links and stops is presented in this study. We proposes a method to compute the optimal route choice of origin-destination pairs and measure the accessibility of the chosen modes combination based on topological configuration. The genetic algorithm is used for the computation of the journey paths, whereas the space syntax theory is used for the accessibility. This study used node-link data in GIS instead of axial lines which are manually drawn in space syntax. The resulting accessibilities of bus stops are calibrated by O-D survey data and the proposed process is tested on a CBD of Seoul.

• Informatization Policy
• /
• v.23 no.3
• /
• pp.43-63
• /
• 2016

This research analyzes the international standardization process by observing the international communication sources in order to understand the reason of its current poor use. Using the 'organizing theory' frame, we observe the initial discourse on the need of internationalized domain names in ICANN and the process of negotiation for technical choice of layers. Lastly, we take Korean domain names as a case study in order to understand the conflict and the cooperation of different stakeholders. We summarize the factors of failure of IDN as follows. First, the need of IDN in the beginning was raised around non-English speaking countries, in Asia and Middle East, with the discourse on 'digital divide solution and cultural value' ICANN rather pursues the 'technical stability of Internet Infrastructure', which made its standardization take as long as 10 years. As a result, a variety of standards and services are proposed in the marketplace, which engendered inefficient competition and domain name-related disputes such as cybersquatting, technical instability and confusion of users. In addition, the government agencies fail to present the appropriate policies adjusting multiple interests of different stakeholders.

• Journal of KIISE:Computer Systems and Theory
• /
• v.27 no.4
• /
• pp.353-361
• /
• 2000

In Computer Graphics, to select the element for modeling is very important in aspect of real-time processing of photorealistic images. Especially in modeling of informal objects, the criteria of choice are such as the minimum number of data, the easy rendering technique, and the expansibility. The metaball model which is one of the methods for modeling the implicit surface is excellent in modeling the complicated surface with a few data. However, a greater number of data are required for modeling objects that consist of planar surfaces with metaballs than with polygons. In this paper, we propose the new skeletal element, metacube which has the merits of metaball and improves the modeling ability of informal objects containing planar surfaces. A metacube has two parameters to change freely its shape from the cube to the sphere and can easily do the modeling of objects with curved surfaces and plane surfaces.

• Journal of KIISE:Computer Systems and Theory
• /
• v.27 no.8
• /
• pp.741-751
• /
• 2000

To achieve high performance by exploiting instruction level parallelism aggressively in superscalar processors, it is necessary to overcome the limitation imposed by control dependences and data dependences which prevent instructions from executing parallel. Value prediction is a technique that breaks data dependences by predicting the outcome of an instruction and executes speculatively its data dependent instruction based on the predicted outcome. In this paper, a hybrid value prediction scheme with dynamic classification mechanism is proposed. We design a hybrid predictor by combining the last predictor, a stride predictor and a two-level predictor. The choice of a predictor for each instruction is determined by a dynamic classification mechanism. This makes each predictor utilized more efficiently than the hybrid predictor without dynamic classification mechanism. To show performance improvements of our scheme, we simulate the SPECint95 benchmark set by using execution-driven simulator. The results show that our scheme effect reduce of 45% hardware cost and 16% prediction accuracy improvements comparing with the conventional hybrid prediction scheme and two-level value prediction scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.7
• /
• pp.2972-2991
• /
• 2016

WLAN is the best choice in the place where complex network is hard to set up. Intelligent terminals are more and more assembled in some areas now. However, according to IEEE 802.11n/802.11ac, the access-point (AP) can only serve one user at a single frequency channel. The spectrum efficiency urgently needs to be improved. In theory, AP with multi-antenna can serve multiple users if these users do not interfere with each other. In this paper, we propose a user clustering scheme that could achieve multi-user selection through the mutual cooperation among users. We focus on two points, one is to achieve multi-user communication with multiple antennas technique at a single frequency channel, and the other one is to use a way of distributed users' collaboration to determine the multi-user selection for user clustering. Firstly, we use the CSMA/CA protocol to select the first user, and then we set this user as a source node using users' cooperation to search other proper users. With the help of the users' broadcast cooperation, we can search and select other appropriate user (while the number of access users is limited by the number of antennas in AP) to access AP with the first user simultaneously. In the network node searching, we propose a maximum degree energy routing searching algorithm, which uses the shortest time and traverses as many users as possible. We carried out the necessary analysis and simulation to prove the feasibility of the scheme. We hope this work may provide a new idea for the solution of the multiple access problem.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.2 no.1
• /
• pp.80-84
• /
• 1999

Dieulafoy's disease, a vascular anomaly mainly in the upper stomach, is a rare but potentially life-threatening cause of upper gastrointestinal bleeding. Pathogenesis is still controversial, but the most accepted theory is that a persistent caliber vessel in the submucosa is exposed by a small mucosal erosion leading to massive bleeding. The bleeding site is usually within 6 cm of the esophagogastric junction in the cardia or fundus of the stomach. The treatment of choice is therapeutic endoscopy or surgery. The age of patients reported is mainly between 50 and 70 years, and patients of pediatric age are extremely rare. We are reporting a 5-year-old male patient who had Dieulafoy's disease which was diagnosed by emergency upper gastrointestinal endoscopy. Endoscopic finding was a nodular lesion with an adherent clot on the lessor curvature of the stomach 2 cm below the esophagogastric junction. Epinephrine and $Beriplast^{(R)}$ was injected in the lesion. On the second day after endoscopic sclerotherapy, the patient had recurred massive hematemesis and accompanying shock. So we performed gastrotomy and ligation. After the operation, he showed an improved general condition and was discharged at the 12th hospital day.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.4
• /
• pp.1130-1147
• /
• 2014

Large size ships have a very flexible construction resulting in low resonance frequencies of the structural eigen-modes. This feature increases the dynamic response of the structure on short period waves (springing) and on impulsive wave loads (whipping). This dynamic response in its turn increases both the fatigue damage and the ultimate load on the structure; these aspects illustrate the importance of including the dynamic response into the design loads for these ship types. Experiments have been carried out using a segmented scaled model of a container ship in a Seakeeping Basin. This paper describes the development of the model for these experiments; the choice was made to divide the hull into six rigid segments connected with a flexible beam. In order to model the typical feature of the open structure of the containership that the shear center is well below the keel line of the vessel, the beam was built into the model as low as possible. The model was instrumented with accelerometers and rotation rate gyroscopes on each segment, relative wave height meters and pressure gauges in the bow area. The beam was instrumented with strain gauges to measure the internal loads at the position of each of the cuts. Experiments have been carried out in regular waves at different amplitudes for the same wave period and in long crested irregular waves for a matrix of wave heights and periods. The results of the experiments are compared to results of calculations with a linear model based on potential flow theory that includes the effects of the flexural modes. Some of the tests were repeated with additional links between the segments to increase the model rigidity by several orders of magnitude, in order to compare the loads between a rigid and a flexible model.

• The Journal of the Korea Contents Association
• /
• v.20 no.1
• /
• pp.73-98
• /
• 2020

This study aims to redefine Vlog, ASMR, and Muk-bang contents as 'Need Fulfillment Video Contents,' which are emerging as major genres among the video contents. And this study explores the relationships between consumers' motives, viewing satisfaction, and consumers' characteristics such as demographic characteristics, big five personality traits, and individualism-collectivism tendencies in terms of uses and gratifications theory. Statistical analysis techniques such as factor analysis and hierarchical regression analysis were used to analyze 441 samples. As a result, age, income level, and collectivism were found to influence consumers' choice of Need Fulfillment Video Content genre. It was also found that the motivation of using Need Fulfillment Video Contents consisted of five factors: self-assessment and improvement, sensory stimulation and relaxation, entertainment, escapism and passing time, and following trends. Also, each usage motive influenced the viewing satisfaction in various ways. Based on the results of the analyses, the study concludes with discussion of the academic significance and practical implications for Need Fulfillment Video Contents industry development.

• Journal of Integrative Natural Science
• /
• v.3 no.4
• /
• pp.226-230
• /
• 2010

Calculation of partial charge is important in chemistry. However, because there are many methods developed, it is of considerable interest to know how to calculate and apply properly to address various chemical problems. For basis set, usually double zeta quality is acceptable, and double zeta polarization function would be enough for most cases. To describe electronic state more accurately, Many electron configurations would be necessary to describe highly strained or anionic species. The NPA population introduced new concept about amide bonds, i.e., the planar geometry of nitrogen atom may not come from resonance, but from the lowering of p-orbital energy by electronegative carbonyl carbon atom. The issues for hypervalent atomic charges was also addressed by various charge derivation scheme. When the charge schemes were applied to organolithium compounds, the ionic nature of boding was revealed. This comes from the fact that previous Mulliken partial atomic charges overemphasized the covalent character, wihout much justification. The other partial charge derivation schemes such as NPA(natural population analysis), IPP (Integrated Projected Population) showed that much more ionic picture. ESP potential derived charges are generally believed to be suitable to describe intermolecular interactions, therefore they are used for molecular dynamics simulations and CoMFA (comparative molecular field analysis). The charge derivation schemes using multipole polarization was mainly applied to reproduce experimental infrared spectroscopy. In some reports these schemes are also suitable for intermecular electrostatic interactions. Charges derived from electron density gradient have shown the some bonds are not straight, but actually bent. The proper choice of charge-calculation method along with suitable level of theory and basis set are briefly discussed.

• Journal of The Korean Association of Information Education
• /
• v.16 no.1
• /
• pp.143-150
• /
• 2012

The choice of occupation has a great deal of influences on achievement of self-realization and living a good life in an individual's life. Especially, it is very significant for Elementary school students because they become to aware of career and develop. However, in the present, the career guidance is mainly concentrated in the solitary work, such as an aptitude test and printed materials. The perspective from the student, therefore, needs systematic and efficient system to accumulate activities and result of their various career guidance for individual career-related information. The system to improve elementary school student's career awareness based on e-portfolio has been developed. The developed system can effectively accumulate students' activities and result of their various career guidance and easily grasp their strengths and weaknesses of intelligence based on theory of multiple intelligences. Teacher also can easily grasp their student's talent through all sorts of graphs provided by the web site for career education.