• Journal of Korean Society for Geospatial Information Science
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• v.24 no.4
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• pp.59-66
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• 2016

For the performance experiments of databases systems with moving object databases, we need moving object trajectory data sets. For example, benchmark data sets of moving object trajectories are required for experiments on query processing of moving object databases. For those reasons, several tools have been developed for generating moving objects in Euclidean spaces or road network spaces. Indoor space differs from outdoor spaces in many aspects and moving object generator for indoor space should reflect these differences. Even some tools were developed to produce virtual moving object trajectories in indoor space, the movements generated by them are not realistic. In this paper, we present a moving object generation tool for indoor space. First, this tool generates trajectories for pedestrians in an indoor space. And it provides a parametric generation of trajectories considering not only speed, number of pedestrians, minimum distance between pedestrians but also type of spaces, time constraints, and type of pedestrians. We try to reflect the patterns of pedestrians in indoor space as realistic as possible. For the reason of interoperability, several geospatial standards are used in the development of the tool.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.1
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• pp.11-27
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• 2017

The road network system of major domestic urban areas such as city of Seoul was rapidly developed and regionally expanded. In addition, many kinds of life-lines such as electrical cables, telephone cables, water&sewerage lines, heat&cold conduits and gas lines were needed in order for urban residents to live comfortably. Therefore, most of the life-lines were individually buried in underground and individually managed. The utility tunnel is defined as the urban planning facilities for commonly installing life-lines in the National Land Planning Act. Expectation effectiveness of urban utility tunnels is reducing repeated excavation of roads, improvement of urban landscape; road pavement durability; driving performance and traffic flow. It can also be expected that ensuring disaster safety for earthquakes and sinkholes, smart-grind and electric vehicle supply, rapid response to changes in future living environment and etc. Therefore, necessity of urban utility tunnels has recently increased. However, all of the constructed utility tunnels are cut-and-cover tunnels domestically, which is included in development of new-town areas. Since urban areas can not accommodate all buried life-lines, it is necessary to study the feasibility assessment system for utility tunnel by urban patterns and capacity optimization for urban utility tunnels. In this study, we break away from the new-town utility tunnels and suggest a quantitative assessment model based on the evaluation index for urban areas. In addition, we also develop a program that can implement a quantitative evaluation system by subdividing the feasibility assessment system of urban patterns. Ultimately, this study can contribute to be activated the urban utility tunnel.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.5
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• pp.1123-1129
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• 2015

Macro(automatic hunting) of mobile game is a program that touch the screen by defined rules like a game bot in PC online games, and it is used by make various ways like android application or windows application program. This gives honest users deprivation and make to lose their interest. Finally they would leave the game and gradually game life would be shorten. Although many studies to prevent these problems in PC online game are conducted, applying mobile game to PC's way is difficult because mobile games are limited to use the network and device performance is different with PC. In this paper, we propose a framework for macro detection by using the touch event information. A touch event on the mobile game is a necessary control command to the game. Because macro touches the screen with the same pattern, there is a difference between normal user's behavior and macro's operation. In mobile games that casual games are mostly, Touch event is the best difference that identify normal user against macro for a short period of time. As a result of detecting macros used in real mobile game by using the proposed framework it showed 100% accuracy and 0% false positive rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.1-8
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• 2016

Current sensors are used widely in the fields of current control, monitoring, and measuring. They have become more popular with the increasing demand for smart grids in a power network, generation of renewable energy, electric cars, and hybrid cars. Although open loop Hall effect current sensors have merits, such as low cost, small size, and weight, they have low accuracy. This paper describes the design and fabrication of a 300A open loop current sensor that has high accuracy and temperature performance. The core of the current sensor was calculated numerically and the signal conditioning circuits were designed using circuit analysis software. The characteristics of the manufactured open loop current sensor of 300 A class was measured at currents up to 300 A. According to the test of the current sensor, the accuracy error and linearity error were 0.75% and 0.19%, respectively. When the temperature compensation was carried out with the relevant circuit, the temperature coefficients were less than $0.012%/^{\circ}C$ at temperatures between $-25^{\circ}C$ and $85^{\circ}C$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2305-2315
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• 2015

Frequency resource value is growing more and more with the development of the wireless communication. With the advent of the current information society comes a serious shortage of frequency resource, as the amount of supply is far from meeting its demands. Thus, cognitive radio (CR) technique is receiving more attention as a way to make use of the temporarily unoccupied frequency resource. In this paper we propose a novel out-of-band spectrum sensing and dynamic channel access scheme for frequency hopping-based cognitive radio ad-hoc networks. At the beginning of each current channel hopping time, member nodes perform spectrum sensing for the next hopping channel. Based on the proposed collision free primary detection notification, member nodes can determine whether they should execute a hopping time extension procedure of the current channel or not. When the primary detected hopping channel is re-idled, the hopping pattern recovery procedure is performed. In this paper we evaluated the performance of the proposed dynamic sensing and hopping channel extension mechanism for the various wireless network conditions. As a result, we show that the proposed method can increase channel utilization and provide reliable channel management operation.

• Archives of design research
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• v.12 no.3
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• pp.227-234
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• 1999

We paid attention to the fact that a project will always tend to increase in size even if its scope is narrowing. The complexities and multidisciplinary aspects of projects require that the many parts should be put together so that the prime objectives- performance, time, and cost- are met. These aspects lead to the use of teams to solve problems that used to be solved by individuals. Firstly, We surveyed the design companies and their clients on the design projects, and categorized the design task into 5 phases, that are marketing, planning, idea development, presentation, and follow-up. Among the phases, the presentation has the most difficult task, longest processing time, and highest cost, whereas idea development phase has relatively low cost, longer processing time, and more difficult task. Most of the companies used to be faced several bottlenecks on their design projects - time control, budget control, and resource control. Secondly, for improving the project managing process, we adopted that dividing and analyzing the sub critical paths may help in the effective managing.(Badiru, Adedeji B., 1995) Some critical paths require almost as much attention as the critical path since they have a high potential of becoming critical when changes occur in the network. Therefrom we suggest the Total task weight(Gt) as a management formula for the design project management.${Gt=\mathrm{T}\ast\leftthreetimes\ast1/100}$<\TEX> ( Gt = Total task weight, mathrm{T} = Task Weight, \leftthreetimes= Criticality ) Thirdly, In order to support to managing for the design projects, we set up an application system, which is graphically planning and implementing a complex undertaking. It is helpful to make the control of a project easy. The DPMS(Design Project Management System), which has two sub system. One is Project Screening System(PSS), and another Project Managing System(PMS). In PMS, we divided the design project into three modules; Project Planning, Project Implementation, and Project Evaluation. As a result, the DPMS will contribute to supply the control of a project easily and effectively. Also teams are used for making decisions and taking action with the DPMS. But we need to get further studies on the relationships between the whole project and its tasks.

• The Journal of Engineering Geology
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• v.12 no.1
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• pp.35-51
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• 2002

This study aims to establish the methodology for design of an optimum water curtain system of the unlined underground oil storage cavern satisfying the requirements of hydrodynamic performance in a volcanic terrain of the south coastal area. For the optimum water curtain system in the storage facility, the general characteristics of groundwater flow system in the site are quantitatively described, i.e. distribution of hydraulic gradients, groundwater inflow rate into the storage caverns, and hydrogeologic influence area of the cavern. In this study, numerical models such as MODFLOW, FracMan/MAFIC and CONNECTFLOW are used for calculating the hydrogeological stability parameters. The design of a horizontal water curtain system requires considering the distance between water curtain and storage cavern, spacing of the water curtain boreholes, and injection pressure. From the numerical simulations at different scales, the optimum water curtain systems satisfying the containment criteria are obtained. The inflow rates into storage caverns estimated by a continuum model ranged from about 120 m$^3$/day during the operation stage to 130~140m$^3$/day during the construction stage, whereas the inflow rates by a fracture network model are 80~175m$^3$/day. The excavation works in the site will generate the excessive decline of groundwater level in a main fracture zone adjacent to the cavern. Therefore, the vertical water curtain system is necessary for sustaining the safe groundwater level in the fracture zone.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.2
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• pp.20-30
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• 1999

We have made the single side hand filter for the dual channel receiver which is a heterodyne receiver to observe the cosmic radio waves with 100GHz band ranged from 85GHz to 115GHz and 150GHz band ranged from 125GHz to 175GHz simultaneously. We have introduced the filter theory using the principle of the Martion-Puplett interferometer, which has the characteristics of rotated polarization. To reduce the loss of the transmission and beam coupling which are caused from the path difference associated with the intermediate frequency the design and the implementation have been intensely considered. The receiver needs two filters with different characteristics each other. Because each of them has the optimum positions as a function frequency at which the signal frequency is fed to mixer and the image frequency is rejected to the image termination load. The intermediate frequency and its band width have been also evaluated. We have measured the property of two filters using the vector network analyser and the beam measurement system which is made by us. The responses of the filter as a function of the position and the frequency are compared with the theory. It is shown that not only the measured values are very close to the theoretical values, but also the image rejection ratios are better than 22dB for both filters. Through successful observation using a dual channel receiver with two manufactured filters, the performance of the filters has finally verified.

• Korean Business Review
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• v.12
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• pp.209-237
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• 1999

With the increasing speed of internationalization of corporations under WTO system foreign direct investment is considered as the important means of international cooperation as well as avoiding trade barrier. From this point of view the study on foreign direct investment of Korean corporations is of great importance. Many studies till now, however, are concerned with the macroscopic analysis of foreign direct investment of Korean corporations, not with the establishment of strategy appropriate to the environment of host country and the investment performance. In order to meet the problems mentioned above this thesis aims at accomplishing the following three tasks. (1) synthetic assessment of existing theories of foreign direct investment. (2) systematic adjustment of factors of environment in the foreign direct investment activities. (3) analysis of above factors in the foreign direct investment of Korean textile industry and proper proposal of strategic model for the individual corporation. The results of analysis according to the aim of the study are as follows: (1) To lead foreign direct investment successfully, variable and effective information-presentation should be offered with priority. (2) The investment strategy through regional diversification is required. (3) The localization of decision making has to be attempted assertively. (4) The global network system is needed for more recommendable foreign direct investment. (5) More aggressive and outgoing attitude like developing into the local market and obtaining the high-technology is desperately needed.

• Journal of Korea Game Society
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• v.9 no.2
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• pp.13-22
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• 2009

Recently, mobile games are developed as the various genre and form with the hardware performance improvement and communication network speed increase of the mobile phone. But it shows the limit of the game material to be developed, because the mobile game has to play by using only the keypad handing of the mobile phone. In this research, 'Flip On / Off interface' and 'Microphone interface' were developed in order to utilize the physical device of the mobile phone as the game interface. 'Flip On / Off interface' and 'Microphone interface' have the advantage that there is no need to purchase a device as an additional interface with utilizing the hardware of the mobile phone itself and the progressing of a game is smooth in comparison with the keypad method of the pre-existence mobile game because the interface waiting time for a call response is short. Moreover, by applying to a commercializing game, the developed interface tests, we confirmed an availability at the commercialization inspection standards on mobile phone without the heap memory deficiency phenomenon to be smooth of an operation. Furthermore, in the result of usability evaluation accessability, reliability, and aesthetics were rated as 'high'. The results of this research reveal that the interface environment of the mobile game limited to a keypad will be able to be made with diversification.