• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.4
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• pp.351-358
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• 2013

We propose a correction method of nonlinear frequency sweep in an FMCW(Frequency Modulated Continuous Wave) laser range finder. FMCW laser range finder requires linear frequency sweep for high resolution, and nonlinear frequency sweep makes the system performance degrade. In general, VCO(Voltage Controlled Oscillator) which is a component used for frequency modulation in FMCW method has nonlinear property. To correct the nonlinear frequency sweep, we utilize an auxiliary delay structure for generating trigger signal of ADC(Analog to Digital Converter). Because the trigger signal has same rate of change with the beat signal, the nonlinearity of the beat signal can be corrected. the experimental results show that the proposed method effectively eliminates the nonlinear frequency sweep problem and enhances the system performance.

• The Transactions of the Korea Information Processing Society
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• v.7 no.9
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• pp.2876-2884
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• 2000

Clausal segmentation is the method that parses Korean sentences by segmenting one long sentence into several phrases according to the predicates. So far most of researches could be useful for literary sentences, but long sentences increase complexities of the syntax analysis. Thus this paper proposed Two-Level Clausal Segmentation using sense information which was designed and implemented to solve this problem. Analysis of clausal segmentation and understanding of word senses can reduce syntactic and semantic ambiguity. Clausal segmentation using Sense Information is necessary because there are structural ambiguity of sentences and a frequent abbreviation of auxiliary word in common sentences. Two-Level Clausal Segmentation System(TLCSS) consists of Complement Selection Process(CSP) and Noncomplement Expansion Process(NEP). CSP matches sentence elements to subcategorization dictionary and noun thesaurus. As a result of this step, we can find the complement and subcategorization pattern. Secondly, NEP is the method that uses syntactic property and the others methods for noncomplement increase of growth. As a result of this step, we acquire segmented sentences. We present a technique to estimate the precision of Two-Level Clausal Segmentation System, and shows a result of Clausal Segmentation with 25,000 manually sense tagged corpus constructed by ETRl-KONAN group. An Two-Level Clausal Segmentation System shows clausal segmentation precision of 91.8%.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.10
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• pp.128-133
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• 2009

This paper describes the comparison and analysis about measurement method of earthing resistance by positions of potential pole and current pole. In KOREA, a diagonal by 6.5 times of earthing electrode for measurement of earthing resistances but this method was almost impossible in the downtown area. For solving this problem, in this paper measuring of earthing resistance changing parameters. The parameter was a distances of earthing electrode, potential pole & current pole and the another parameter was an angles of potential pole & current pole. Analysis result, earthing resistance stability that conditions. Fist, distance from earthing electrode to current pole was over 50[m] and distance from earthing electrode to potential pole was over 30[m]. Second, angles of potential pole & current pole was over $45[^{\circ}]$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.395-402
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• 2016

This paper presents a design methodology for improving the energy efficiency by considering the inertial properties of serial manipulators. This method employed is to put the inertia matrix, which has a critical effect on the equation of motion, into the constraints of the optimization problem. Through the optimization process, we propose a design algorithm that can double-check whether the optimized parameters satisfy the required performance or not by using an auxiliary index associated with the inertia and energy. Using this design algorithm, we were able to improve the energy efficiency by minimizing the torque. We applied this method to a 3 degrees of freedom serial manipulator and simulated it.

• Journal of Industrial Convergence
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• v.17 no.4
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• pp.125-129
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• 2019

With the growing number of people using bicycle, the number of bicycle accidents also has been increasing. It is said that bicycle accident can be reduced up to 11%~44% when riding a bicycle if LED light is used. The headlight of the bicycle makes exposure effect to the opposite side of bike rider while taillight makes exposure effect to the rear bike rider for improving safety. Bicycle safety device capable of displaying a change of direction by LED is implemented in this study in response to control button signal. This signal makes LED light which is installed in pedal and wheel of bicycle as a module type emitting or flickering during the fixed hour. Bicycle auxiliary device in pedal which is able to improve safety using LED when bikers are riding a bike at night is developed in this study. Bicycle safety device applying wireless communication technology will be expected alternative technology in the future to solve a social problem such as energy, environment, and safety.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.1
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• pp.3-11
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• 2003

Face stability of a tunnel is a main concern during tunnel excavation. However, there has been only a few studies on this problem while a lot of researches on the support systems have been carried out. In addition, when tunneling is performed below the groundwater level, the groundwater flows into the tunnel so that the seepage forces generated on the tunnel face might give rise to a serious potential for the face instability. In this study, the face stability was evaluated by simultaneously considering two factors: one is the effective stress calculated by upper bound theorem; the other is the seepage forces acting on the tunnel face obtained by numerical analysis under the condition of steady-state groundwater flow. Tunneling in difficult geological conditions often requires auxiliary techniques to guarantee safe tunnel excavations and/or to prevent damage to structures and services around the tunnel. The steel pipe-reinforced multistep grouting has been recently applied to tunnel sites in Korea. Face stability of a tunnel with the steel pipe-reinforced multistep grouting was also analyzed in this study.

• Journal of KIISE:Software and Applications
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• v.27 no.7
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• pp.784-793
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• 2000

The conventional morphological analysis of Korean language presents various morphological ambiguities because of its agglutinative nature. These ambiguities cause syntactic ambiguities and they make it difficult to select the correct parse tree. This problem is mainly related to the auxiliary predicate or bound noun in Korean. They have a strong relationship with the surrounding morphemes which are mostly functional morphemes that cannot stand alone. The combined morphemes have a syntactic or semantic role in the sentence. We extracted these morphemes from 0.2 million tagged words and classified these morphemes into three types. We call these morphemes a syntactic morpheme and regard them as an input unit of the syntactic analysis. This paper presents the syntactic morpheme is an efficient method for solving the following problems: 1) reduction of morphological ambiguities, 2) elimination of unnecessary partial parse trees during the parsing, and 3) reduction of syntactic ambiguity. Finally, the experimental results show that the syntactic morpheme is an essential unit for reducing morphological and syntactic ambiguity.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.1
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• pp.47-57
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• 2010

Subgrid scale stabilization method is applied to Woo and Liu(2004)'s extended Boussinesq FEM numerical model to eliminate the 2dx wiggles. In order to optimize the computational efficiency, Hessian operator is introduced and the matrix of velocity vector is combined to one matrix for solving matrix equations. The mass lumping technique is also applied to the matrix equations of auxiliary variables. The newly developed code is applied to simulate Vincent and Briggs(1989)' wave transformation experiments and the results show that the numerical solution is almost wiggle-free and it matches very well with experimental data. Due to improvement of computational efficiency and wiggle reduction, it is plausible to apply this model to a realistic problem such as harbor oscillation problems.

• Journal of KIISE
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• v.43 no.4
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• pp.404-410
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• 2016

Automated road map generation poses significant research challenges since GPS-based navigation systems prevail in most general vehicles. This paper proposes an automated detecting method for intersection points using GPS vehicle trajectory data without any background digital map information. The proposed method exploits the fact that the trajectories are generally split into several branches at an intersection point. One problem in previous work on this intersection detecting is that those approaches require stopping points and direction changes for every testing vehicle. However our approach does not require such complex auxiliary information for intersection detecting. Our method is based on partial trajectory matching among trajectories since a set of incoming trajectories split other trajectory cluster branches at the intersection point. We tested our method on a real GPS data set with 1266 vehicles in Gangnam District, Seoul. Our experiment showed that the proposed method works well at some bigger intersection points in Gangnam. Our system scored 75% sensitivity and 78% specificity according to the test data. We believe that more GPS trajectory data would make our system more reliable and applicable in a practice.

• Fashion & Textile Research Journal
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• v.2 no.3
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• pp.265-271
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• 2000

Heat stress results in fatigue, a decline in strength, alertness., and mental capacity. The problem is compounded when high humidity exists. To help relieve worker heat stress, many types of cooling units are marketed. While workers may experience some cooling, critical body core temperatures often continue to elevate. This study was designed to find the effects of three kinds of cooling vest with portable frozen gel strips on thermophysiological parameters and on temperature and humidity within clothing. The heart rate, rectal, and skin temperature as well as sweat rate and clothing microclimate were measured during 80 min in 5 healthy males. Inquiries were also made into the subjective rating thermal, humidity comfort, and fatigue sensations. The main findings in our experiments are as follows: (a) Physiological parameters such as rectal temperature was the lowest in garb A1, intermediate in garb A, and the highest in garb A2 throughout the experiment. And mean skin temperature was the lowest in garb A, intermediate in garb A1, and the highest in garb A2; (b) Temperature and humidity within clothing (back) were garb in Al, intermediate in garb A, and the highest in garb A2. But the temperature and humidity within clothing (chest) were garb in A, intermediate in garb A1, and the highest in garb A2; (c) Most participants (4 out of 5 persons) answered that they felt more comfortable and fatigueless in garb A1 than in garb A and A2. It is concluded that local cooling in garb A1 of the upper torso could physiological reduce the thermal strain in participants wearing cooling vest.