• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.146-149
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• 2008

Simulation and signal conditioning on the time domain surface elevation records are conducted to verify the proposed Welch's method in non-directional ocean wave spectrum analysis. These spectrum data are further conditioned to provide wave characteristic that better describe the sea states. Comparison of significant wave height and zero crossing period between the proposed method and a reference toolkit are presented.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.733-736
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• 1999

In this Paper, Bit selectable and Bi-directional Interface Port is described, which can communicate data with the peripheral devices. Specially A description of the asynchronous design method is given to remove the clock skew phenomenon and the output asynchronous control method which finds the optimal clock and controls all the enable signal of the output pins at the same time is presented. Using this technique interface ports have delay time of less-than 0.5㎱.

• Journal of the Korean Statistical Society
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• v.33 no.3
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• pp.255-269
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• 2004

This paper develops log-density estimation for directional data. The methodology is to use expansions with respect to spherical harmonics followed by estimating the unknown parameters by maximum likelihood. Minimax rates of convergence in terms of the Kullback-Leibler information divergence are obtained.

• Journal of the Korean Geotechnical Society
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• v.22 no.4
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• pp.11-19
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• 2006

For the last decade, the hi-directional testing method has been advantageous over the conventional pile load testing method in many aspects. However, because the hi-directional test uses a loading mechanism entirely different from that of the conventional pile load testing method, many investigators and practicing engineers have been concerned that the hi-directional test would give inaccurate results, especially about the pile head settlement behavior. Therefore, a hi-directional load test and the conventional top-down load test were executed on 1.5 m diameter cast-in-situ concrete piles at the same time and site. Strain gauges were placed on the piles. The two tests gave similar load transfer curves at various depth of piles. However, the top-down equivalent curve constructed from the hi-directional load test results predicted the pile head settlement under the pile design load to be about one half of that predicted by the conventional top-down load test. To improve the prediction accuracy of the top-down equivalent curve, a simple method that accounts for the pile compression is proposed. It was also shown that the strain gauge measurement data from the hi-directional load test could reproduce almost the same top-down curve.

• The KIPS Transactions:PartA
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• v.14A no.5
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• pp.287-294
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• 2007

Most of existing integrated remote controllers can control only a group of home appliances made by the same manufacturer. And they cannot monitor the status of home appliances since they are based on analog RF(Radio Frequency) signal and operate in a uni-directional manner In this paper, we propose a software framework for a hi-directional universal remote controller(URC) which monitors the status of home appliances in Wireless Personal Area Network(WPAN). The URC can handle the control and status messages which consist of a command with related arguments. When a user wants to control any home appliance, the URC can be dynamically configured to its dedicated remote controller by generating a GUI according to its profile. Any other devices which have a capacity for understanding the profile from the controlled devices can play the same role of the URC.

• Journal of Navigation and Port Research
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• v.37 no.2
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• pp.195-201
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• 2013

Recently according to increase of enlarged scale ports in conformity with increase in over size vessels and container handling service, pollutants generated from ports are increasing. In advanced countries, reduction in carbon dioxide emission assigned to them has been implemented according to the Climate Change Convention and Kyoto Protocol from 2008 to 2012 in order to lessen carbon dioxide emission. Henceforth increase in discussion on the measure of constructing Green Port and low-carbon port is expected in our nation's field of port as well, it is considered that the effort in reduction with regard to undesirable output which causes environmental problem of analysis target during measuring effectiveness. Therefore, in this study, effectiveness was estimated through directional technology distance function considering undesirable output differently from effectiveness analysis of existing container terminal, and then performed comparative analysis with the result analyzed with BCC output-oriented model. As the result of analysis, in 2007 DMU3 and DMU5, and in 2010 DMU2 and DMU4 appeared to be efficient terminals in BCC output oriented model, and in directional technology distance function model, DMU1, DMU3 in 2007, DMU3, DMU5 in 2008, DMU7 in 2009, and DMU2, DMU5 in 2010 appeared to be efficient terminals.

• Journal of electromagnetic engineering and science
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• v.19 no.1
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• pp.20-30
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• 2019

A wide-band multiple-input multiple-output (MIMO) antenna with dual-band (2.4 and 5 GHz) operation is proposed for premium indoor access points (IAPs). Typically, an omni-directional pattern is used for dipole antennas and a directional radiation pattern is used for patch antennas. In this paper, both antenna types were used to compare their performance with that of the proposed $2{\times}2$ MIMO antenna. We simulated and measured the performance of the MIMO antenna, including the isolation, envelope correlation coefficient (ECC), mean effective gain (MEG) for the IAPs, and the throughput, in order to determine its communication quality. The performance of the antennas was analyzed according to the ECC and MEG. The proposed antenna has sufficient performance and excellent characteristics, making it suitable for IAPs. We analyzed the communication performance of wireless networks using the throughput data of a typical office environment. The network throughput of an 802.11n device was used for the comparison and was conducted according to the antenna type. The results showed that the values of the ECC, MEG, and the throughput have unique characteristics in terms of their directivity, antenna gains, isolation, etc. This paper also discusses the communication performance of various aspects of MIMO in multipath situations.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1169-1176
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• 2018

The C-band omni-directional antenna for drone control is mounted on the top or bottom and used to configure the communication link. The communication link is affected by the LOS depending on the mounting position of the omni-directional antenna. In this paper, two kinds of embedded antennas were designed with a commercial simulation tool CST MWS, and EM analysis was performed to consider the mounting environment. Also, we propose the PTMP ground antenna to control a large number of drones. The ground antenna has a communication link of 30km, and it consists of four sector antennas in the horizontal direction and one directional antenna at the top.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.824-827
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• 1996

Most autonomous mobile robots view things only in front of them. As a result, they may collide against objects moving from the side or behind. To overcome the problem we have built an Active Omni-directional Range Sensor that can obtain omnidirectional depth data by a laser conic plane and a conic mirror. In the navigation of the mobile robot, the proposed sensor system makes a laser conic plane by rotating the laser point source at high speed and achieves two dimensional depth map, in real time, once an image capture. The experimental results show that the proposed sensor system provides the best potential for navigation of the mobile robot in uncertain environment.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.754-759
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• 2008

Recently, the construction of buildings and large bridges has been increasing rapidly causing foundation structure growing larger then before, especially in the use of large size cast-in-place piles. Barrette Pile will usually be used at the site where diaphragm wall is the retaining wall to save time and cost in mobilization of equipments. This study uses bi-directional loading test data obtained from two different sites to observe the bearing capacity and displacement characteristics of barrette pile. Numerical analysis of the test is done by using commercial 3D computer program and the interface effect and capacity of the pile as well as displacement characteristics of the pile is verified.