• Journal of Korean Society for Geospatial Information Science
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• v.4 no.2 s.8
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• pp.123-136
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• 1996

Lately, the demand for data standardization become increased to obtain various data jointly along with development of information technology and diversity of society. Thus the research on tile definition and evaluation of data quality indicating accuracy and confidence of geospatial data, is required for this standardization. In this study, by virtue of comparison of definitions and evaluation methods of data quality element being selected from representative countries, the following results were obtained: (1) Application of ISO/TC211's Draft having accepted evaluation standard to KSDTS(Korea Spatial Data Transfer Standard) is desirable for definitions of data quality elements. (2) This study presented the quality evaluation of much more resonable geospatial data accompaning with quality element. Furthermore, this study suggests that this evaluation be applicable to KSDTS and be contained in the digital map product specification of National Geography Institute with more clearness of a report form of data quality evaluation result. (3) Studies on various sampling methods, establishment of AQL(Acceptable Quality Level) suitable for our country, and computer programming which can rapidly and automatically evaluate mass much of data are required.

• Journal of the Korean Society of Hazard Mitigation
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• v.1 no.1 s.1
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• pp.157-163
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• 2001

The objective of the present study is to predict the characteristics of the fire and smoke propagations in a clean room. Numerical calculations have been performed by using the finite volume method to obtain temperature and velocity distributions in the clean room. In odor to account for the turbulent flow characteristics, the standard $k-{\varepsilon}$ model is used. From this study, it was found that the fire propagation could be fully developed only after 150 seconds when the ventilation system in the clean room was off. And the smoke mass fraction showed a similar distribution as the gas temperature. Since the simulated fire was proceeded up to $20{\sim}30%$ of the room within 60 seconds. it could be recommended that the occupants should be evacuated from the room within 30 seconds.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.7
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• pp.51-60
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• 2002

The Monte-Carlo simulation of statistical analysis is used to investigate the final conditions of states as well as the footprint boundaries resulting from the atmospheric re-entry dispersions. The re-entry dispersions in this paper are specified by a $7\times7$ covariance matrix of latitude, longitude, altitude, bank angle, flight path angle, heading error, and range at entry velocity. The error sources that affect these at re-entry for a deboost are the uncertainties associated with atmospheric density and temperature, initial errors, wind, and estimation error of aerodynamic coefficients. Using $3{\sigma}_n$ deviations of these errors and a nominal flight trajectory, the covariance matrix of state variables can be determined by performing a trajectory error analysis. Major considerations in the application of the Monte-Carlo method are the simulation of perturbed trajectories, bank reversal, and determination of the impact points for each of these trajectories. This paper analyzes the results of uncertainties from the viewpoint of aero-coefficients and bank reversal.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.9 no.2
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• pp.37-48
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• 1991

In this study, conventional network adjustment and combined network adjustment methods for single network adjustment methods for single network and centric combination network were compared by the analysis of root mean square error and standard error ellipse of observed points. It can be concluded from this study that for conventional surveying methods, the accuracy is in theorder of trilateration, traverse and triangulation, and for the case of combined surveying method, the accuracy is in the order of multilateration surveying, combined traverse and combined triangulation-trilateration surveying. And when establishing new control points, the accuracy can be improved by increasing redundant observations of centric combination network instead of using the single network. Also, in case of combined traverse surveying by adding observable laterals, accuracy level of trilateration could be achieved, and it was found that traverse is effective for large areas where sighting is easy, and combined traverse surveying is effective for urban areas where sighting is difficult.

• Journal of Korean Society for Geospatial Information Science
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• v.3 no.2 s.6
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• pp.115-130
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• 1995

The National Geographic Institute(NGI), a national mapping agency, has begun to digitalize national base maps to vitalize nation-wide GIS implementations. However, the NGI's cartographic database design reflects only paper map production and is considered inflexible for various applications. In order to suggest an appropriate data model and database implementation method, approaches of two mapping agencies are analyzed: the United State Geological Survey and Ordnance Survey in the United Kingdom One important finding from the analysis is that each data model is designed to achieve two production purposes in the same time : map and data. By taking advantageous features from the two approaches, an ideal model is proposed. To adapt the ideal model to tile present situation in Korean GIS community, a realistic model is generated, which is an 'SDTS-oriented' data model. Because SDTS will be a Korean data transfer standard, it will be a common basis in developing other data models for different purposes.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.113-116
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• 2008

According to a domestic provision, test levels of the barrier are divided into seven categories(SB1 to SB7) and the corresponding crash conditions are specified. Meanwhile, standard types of concrete barriers with different dimensions have been constructed nation wide. Some studies aimed at finding a proper test level of each type of the concrete barrier have been carried out, but the reliable and consistent results have not been fully established yet. The purpose of this study is to find out the test level corresponding to the concrete barrier of type-2 through static test. AASHTO LRFD was referred to for the loading pattern and a magnitude of the load that simulate a vehicle crash assumed. The test results show that the ultimate strength of the type-2 satisfies the load level required for SB5. However, it seems that the type-2 does not comply with SB6, showing some differences in results from previous analytical studies. In order to take advantage of the static test in establishing the test level of the domestic barrier, more detailed provisions should be specified.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6C
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• pp.601-609
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• 2002

The efficient Viterbi decoder that supports full data-rate output of DAB system was proposed. Viterbi decoder consumes lots of computational load and should be designed to be fast specific hardware. In this paper, SST scheme was adopted for Viterbi decoder with puncturing to reduced the power consumption. Puncturing vector tables are modified and re-arranged to be designed by a hardwired logic to save the system area. New re-scaling scheme which uses the fact that the difference of the maximum and minimum of the path metric values is bounded is proposed. The proposed re-scaling scheme optimizes the wordlength of path metric memory and greatly reduces the computational load for re-scaling by controlling MSB of path metric memory. Another saving of computation is done by proposed algorithm for branch metric calculation, which makes use of pre-calculated metric values. The designed Viterbi decoder was synthesized using SAMSUNG 0.35$\mu$ standard cell library and occupied small area and showed lower power consumption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12C
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• pp.983-990
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• 2008

In communication systems, initial acquisition is required for the reliable transmission performance, and the analysis of the acquisition performance over various communication environments including different signal-to-noise ratios plays an important role in communication system design. Usage of differential correlation methods in initial synchronization procedure is desired when frequency offsets exist, and additional performance improvement can be achieved through proper modifications of conventional correlation schemes. In this paper, we derive the error probability of the initial acquisition and express it in terms of the Marcum Q-function, via statistical modeling of the differential correlator output. The result is generalized to the error probabilities of the extended differential correlation methods using the complex- and magnitude-sum of the correlator outputs. The derived probabilities can be applied for the acquisition performance verification of various communication systems including the DVB-S2 standard.

• The KIPS Transactions:PartD
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• v.15D no.1
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• pp.73-86
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• 2008

Because of its capability of automatic identification of objects, RFID(Radio Frequency Identification) technologies have extended their application areas to logistics, healthcare, and food management system. Load balancing is a basic technique for improving scalability of systems by moving loads of overloaded middlewares to under loaded ones. Adaptive load balancing has been known to be effective for distributed systems of a large load variance under unpredictable situations. There are needs for applying load balancing to RFID middlewares because they must efficiently treat vast numbers of RFID tags which are collected from multiple RFID readers. Because there can be a large amount of variance in loads of RFID middlewares which are difficult to predict, it is desirable to consider adaptive load balancing approach for RFID middlewares, which can dynamically choose a proper load balancing strategy depending on the current load. This paper proposes an adaptive load balancing approach for RFID middlewares and presents its design and implementation. First we decide a performance model by a experiment with a real RFID middleware. Then, a set of proper load balancing strategies for high/medium/low system loads is determined from a simulation of various load balancing strategies based on the performance model.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.373-381
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• 1997

In order to investigate the drift of pesticides sprayed on Chinese cabbage, 7 pesticides chlorpyrifos, EPN, pirimiphos-methyl, phenthoate, tetradifon, dicofol and bifenthrin were applied in two sets of field tests. The pesticide residues were quantified bar multiple-residue analysis, in which the recovery rate was 78${\sim}$92% and standard deviation was ${\pm}0.683{\sim}52%$. It was found that most of the tested pesticides were spread by drift to neighbouring area and brought about the contamination of the unsprayed crops. The extent of drift varied depending upon the pesticide, distance and wind direction. The mean residue levels on unsprayed crops were 0.66% at 3 meter distance, 0.10% at 6 m distance and 0.05% at 9 m distance from the applied area and the maximum level was 1.83% of the residue on sprayed crops.