• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.2
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• pp.143-149
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• 2011

In this paper, IIR structures are proposed to reduce the computation complexity of the secondary-pass estimation in active noise control(ANC) systems. However, there are stability problems of using IIR models to reduce the computation complexity in ANC systems. To overcome these problems, we propose a stabilizing procedure of recursive least mean squares (RLMS) algorithms for eatimating the parameters of IIR models of the secondary path transfer functions. The multichannel ANC systems are implemented by using the TMS320C6713 DSP board to test the performance of computation complexity and stability of the proposed methods. Comparing the IIR filters with the FIR filters, the IIR filters can reduce 50[%] of the computation and obtain similar noise reduction result.

• Journal of Biosystems Engineering
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• v.26 no.3
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• pp.237-244
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• 2001

This work was intended to investigate the effect of vibration transmission paths on the ride vibration of tractor during the rotavating and transporting operations by applying the vibration path analysis method. Accelerations at the cab mounts were measured during the rotavating and transporting operations. Ride vibrations at the sear were than calculated using the measured accelerations at the cab mounts, and the frequency response functions and inertances between the seat and cab mounts, which were derived experimentally by the impact hammer test in static condition. The human sensitivity to vibration frequency was also taken into consideration for the calculation of ride vibrations at the 1/3 octave center frequencies in the frequency domain. Vibrations transmitted through rear cab mounts affected more significantly the ride vibration of tractor. The peak accelerations at the seat occurred at the frequencies of the engine and crank speed, and the frequency induced by tire lugs on the road transportation. It was found that the rear cab mounts should be improved in order to reduce the ride vibrations more effectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.4
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• pp.57-65
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• 2010

In this paper we proposed channel models for terrestrial ATSC (Advanced Television Systems Committee) DTV (Digital Television) system in South Korea. For the purpose of this model, we research on propagation model involved in terrestrial DTV system and analyze out field test data of terrestrial DTV broadcasting carried out in korean Broadcasting System. Using the measured values of received field strength, newly proposed Path-loss models have more correctly than that of conventional Path-loss models. This models can be utilized usefully for the efficient ATSC DTV system implementation requiring accurate link-budget calculation

• KIEAE Journal
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• v.5 no.1
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• pp.35-42
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• 2005

The primary concerns of recreation plan are to provide visitors with quality of recreational experience and to protect of recreation resources. The quality of recreational experience is often defined in terms of social carrying capacity. The carrying capacity is revealed as perceived crowding. In this respects, measuring perceived crowding is useful tool of social carrying capacity determination. This study is to test the structural equation model that includes variables affecting perceived crowding. Through an on-site questionnaire survey, 467 visitors on Naejangsan national park were collected. The results of the study are follows. The encounter level on facility area is higher evaluated as crowding factor than other area in the park. It can be concluded that visitor perceived crowding when facility area situates high density use level rather than other areas expose high density use level. In the path analysis, the input variables(attitude, experience, encounter level) on the structural equation model affect significantly on perceived crowding. Especially, the attitude on the park management polocy is the most affecting factor on perceived crowding.

• Transactions of Materials Processing
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• v.6 no.5
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• pp.400-407
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• 1997

Geometric mapping technique has been used to find the shape of initial blank for sheet forming. The method was chosen because of its simplicity and numerical efficiency. Error in blank shape were measured along deformation path by FE analysis of forming. Blank shape was modified by volume additionaddition/Subtractiontraction method with taking with taking into account of deformation path. Modified blank shape shows an acceptable result, showing the current method can be an useful tool for predicting blank shape in the practical application. More test will be done to verify the validity of the method.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.303-310
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• 2000

A new stress path testing scheme with back pressure equalization process is proposed, to compute the settlement of clay soils based on their probable deformation mode. The proposed testing scheme minimizes the efforts for testing, otherwise numerous testing works are required to simulate the probable stress paths in the field. Furthermore, the proposed testing scheme can supply anisotropic stress paths for consolidation which cannot be possible in a conventional way. The validity and effectiveness of the proposed testing scheme was investigated and confirmed with test results on remolded kaolinite clay soils. Conclusively, it is suggested that the proposed testing scheme is a very effective tool to compute settlement of clay soils and it is also very useful to investigate the anisotropic characteristics of deformation of clay soils.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.184-195
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• 1996

Beause BiCMOS logic circuits consist of CMOS part which constructs logic function and bipolar part which drives output load, the effect of short faults on BiCMOS logic circuits represented different types from that on CMOS. This paper proposes new test method which detects short faults on BiCMOS logic circuits using current path graph. Proposed method transforms BiCMOS circuits into raph constructed by nodes and edges using extended switch-level model and separates the transformed graph into pull-up part and pull-down part. Also, proposed method eliminates edge or add new edge, according ot short faults on terminals of transistor, and can detect short faults using current path graph that generated from on- or off-relations of transistor by input patterns. Properness of proposed method is verified by comparing it with results of spice simulation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.3
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• pp.30-39
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• 2010

This paper considers a problem of optimizing torch paths to cut stock plates nested with open contours. For each contour, one of the two ending points is to be selected as a starting point of cutting with the other being the exit point. A torch path is composed of a single depot and a series of starting and ending points of contours to be cut. The torch path optimization problem is shown to be formulated as an extended version of the standard travelling salesman problem. To solve the problem, a hybrid genetic algorithm with the local search of torch paths is proposed. The genetic algorithm is tested for hypothetical problems whose optimal solutions are known in advance due to the special structure of them. The computational results show that the algorithm generates very near optimal solutions for most cases of the test problems, which verifies the validity of the algorithms.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.6
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• pp.990-997
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• 2010

The Mission environment of UGV(Unmanned Ground Vehicle) has a complexity and variety, and the status of system and sensor is dependent on the environment factors such as operation time, the weather and road type. It is necessary for UGV to cope adaptively with the various mission types, operation modes and operation environment as human operators do. To satisfy this necessity, we present an autonomy manager based on the autonomous architecture. In this paper, we design a path planning software architecture and LPP manager by using open autonomous architecture which is previously designed by ADD. Field test is conducted with UGV in order to verify the performance of LPP Manager based on the Autonomous Architecture with scenarios.

• Korean Journal of Child Studies
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• v.27 no.6
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• pp.249-261
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• 2006

This study investigated the influence of socio-environmental variables and cognitive variables on adolescent depression. Subjects were 494 middle and high school students of Deagu. The instrument was a self-report questionnaire; data were analyzed by t-test, stepwise multiple regression and path analysis. Among Socio-environmental variables, social support variables had a stronger effect on depression than stress. Among cognitive variables, automatic thought had a stronger effect on depression than cognitive distortion and socio-environmental variables. In path analysis, social support had a direct effect on cognitive distortion and automatic thought. Automatic thought served as a mediater of the relation between social support and depression. Although adolescent stress resulted in high depression, its effect on depression varied with the level of perceived social support.