• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.69-76
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• 2015

In this paper, we propose and analyze a M-ary transmission scheme in time hopping ultra-wide band(UWB) system using mutually orthogonal modified Hermite polynomial(MHP) pulses. The proposed M-ary transmission scheme employs the orthogonal property between different ordered pulses and N data bits make the M-ary signals by linear combination of M MHP pluses. The theoretical analysis and simulation results show that the proposed system has better performance and higher data rate than conventional M-ary UWB system. We derive the general form of correlation function for MHP pulses and analyze bit error rate(BER) performance over additive white Gaussian noise(AWGN) with the presence of timing jitter. We show that the proposed system has the improved BER performance and robustness to timing jitter and low power spectrum density compared with conventional M-ary UWB system.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.578-588
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• 2017

The purpose of this paper was to prove the January Effect and Efficiency of the KOSPI Market, and then suggest as a result. KOSPI data was divided into two of section, Before and After IMF Financial Crisis, and this paper utilized Market Capitalization of common stock to conduct a study. As the main findings of this result, in KOSPI 1st section(Before IMF Financial Crisis), this paper proved the January Effect and Size Effect for Small-capital stock. On the other hand, in KOSPI $2nd-{\alpha}$ & ${\beta}$ section(After IMF Financial Crisis), this paper couldn't prove the January Effect. And then, this paper couldn't prove the Efficient Market hypothesis in KOSPI 1st with January Effect, however, proved the weak efficient market in KOSPI 2nd(${\alpha}$ & ${\beta}$) without January Effect. Finally, this paper deducted implications and limitation as the results.

• Journal of the Korean Society for Railway
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• v.18 no.4
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• pp.344-353
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• 2015

Recently, the utilization of the BIM system has been extended to cost and resource simulation, visualized management of construction site information and application of augmented reality including basic 3D modeling. Therefore, various BIM functions are being developed for practical applications. However, since clear classification criteria and knowledge information of BIM functions are not sufficient for field engineers, it is difficult to identify the necessary BIM functions for a construction project. This study suggests a BIM function breakdown structure considering the individual functional properties and a process model that can be ordered by applying BIM in a railway construction project. The proposed delivery model is used to obtain a practical utilization of BIM by analyzing features applicable to railway construction projects; model is verified using a case project.

• Korean Journal of Construction Engineering and Management
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• v.18 no.5
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• pp.41-49
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• 2017

The ordering organizations of civil engineering project manage the construction site indirectly because the construction site is mostly located at a remote location and the public official also manages many sites. Since the civil engineering project has a wide working area, it is not easy to know the status of the whole project quickly by the indirect management method by report of the field practitioner. In order to solve these problems, the field management system between the ordering organization and the field office is changing from offline to online. This study suggests an advanced construction site management system that obtains site-related 3D information with the use of UAV and shares the information between the construction site in remote locations and their supervising authorities. To develop an UAV application system, the problems of field management in many actual sites were analyzed and derived necessary functions such as status reporting and online information management. The developed system was applied to actual field to verify its usability and compared the efficiency improvement with existing field management method.

• The Journal of the Korea Contents Association
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• v.8 no.2
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• pp.41-47
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• 2008

There exists a many-to-many mapping relationship between persons and their names. A person may have multiple names, and different persons may share the same name. These synonymous and homonymous names may severely deteriorate the recall and precision of the person search, respectively. This study addresses the characteristics of features for resolving homonymous author names appearing in citation data. As disambiguation features, previous works have employed citation-internal features such as co-authorship, titles of articles, titles of publications as well as citation-external features such as emails, affiliations, Web evidences. To the best of our knowledge, however, there has been no literature to deal with the influences of features on author disambiguation. This study analyzes the effect of individual features on author resolution using a large-scale test set for Korean.

• Journal of KIISE:Software and Applications
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• v.33 no.12
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• pp.1022-1030
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• 2006

The location awareness is an important part of many ubiquitous computing systems, but a perfect location system does not exist yet in spite of many researches. Among various location tracking systems, we choose the RFID system due to its wide applications. However, the sensed RSSI signal is too sensitive to the direction of a RFID reader antenna, the orientation of a RFID tag, the human interference, and the propagation media situation. So, the existing location tracking method in spite of using the particle filter is not working well. To overcome this shortcoming, we suggest a robust location tracking method with a double layered structure, where the first layer coarsely estimates a tag's location in the block level using a regression technique or the SVM classifier and the second layer precisely computes the tag's location, velocity and direction using the particle filter technique. Its layered structure improves the location tracking performance by restricting the moving degree of hidden variables. Many extensive experiments show that the proposed location tracking method is so precise and robust to be a good choice for implementing the location estimation of a person or an object in the ubiquitous computing. We also validate the usefulness of the proposed location tracking method by implementing it for a real-time people monitoring system in a noisy and complicate workplace.

• Journal of Intelligence and Information Systems
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• v.15 no.1
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• pp.51-64
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• 2009

A location tracking sensor such as GPS, INS, Radar, and optical equipments is used in tracking Maneuvering Targets with a multi-sensor, and such systems are used to track, detect, and control UAV, guided missile, and spaceship. Until now, Most of the studies related to tracking Maneuvering Targets are on fusing multiple Radars, or adding a supplementary sensor to INS and GPS. However, A study is required to change the degree of application in fusions since the system property and error property are different from sensors. In this paper, we perform the error analysis of the sensor properties by adding a ground radar to GPS and INS for improving the tracking performance by multi-sensor fusion, and suggest the tracking algorithm that improves the precision and stability by changing the sensor probability of each sensor according to the error. For evaluation, we extract the altitude values in a simulation for the trajectory of UAV and apply the suggested algorithm to carry out the performance analysis. In this study, we change the weight of the evaluated values according to the degree of error between the navigation information of each sensor to improve the precision of navigation information, and made it possible to have a strong tracking which is not affected by external purposed environmental change and disturbance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.4
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• pp.700-708
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• 2015

A software birthmark is the set of characteristics of a program which can be used to identify the program. Many researchers have studied on detecting theft of java programs using some birthmarks. In case of Android apps, code obfuscation techniques are used to protect the apps against reverse-engineering and tampering. However, attackers can also use the obfuscation techniques in order to conceal a stolen program. A birthmark (feature) of an app can be alterable by code obfuscations. Therefore, it is necessary to detect Android app theft based on the birthmark which is resilient to code obfuscation. In this paper, we propose an effective Android app birthmark and app theft detection through the proposed birthmark. By analyzing some obfuscation tools, we have first selected parameter and the return types of methods as an adequate birthmark. Then, we have measured similarity of target apps using the birthmarks extracted from the apps, where some target apps are not obfuscated and the others obfuscated. The measurement results show that our proposed birthmark is effective for detecting Android app theft even though the apps are obfuscated.

• Journal of KIISE:Databases
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• v.41 no.4
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• pp.249-255
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• 2014

Copy number variations(CNVs) are a recently recognized class of human structural variations and are associated with a variety of human diseases, including cancer. To find important cancer genes, researchers identify novel CNVs in patients with a particular cancer and analyze large amounts of genomic and clinical data. We present a tool called CNVDAT which is able to detect CNVs from NGS data and systematically analyze the genomic and clinical data associated with variations. CNVDAT consists of two modules, CNV Detection Engine and Sequence Analyser. CNV Detection Engine extracts CNVs by using the multi-resolution system of scale-space filtering, enabling the detection of the types and the exact locations of CNVs of all sizes even when the coverage level of read data is low. Sequence Analyser is a user-friendly program to view and compare variation regions between tumor and matched normal samples. It also provides a complete analysis function of refGene and OMIM data and makes it possible to discover CNV-gene-phenotype relationships. CNVDAT source code is freely available from http://dblab.hallym.ac.kr/CNVDAT/.

• Journal of Satellite, Information and Communications
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• v.12 no.3
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• pp.108-113
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• 2017

The OBCP called 'operator on board' is that of a procedure to be executed on-board, which can be easily be loaded, executed, and also replaced, without modifying the remainder of the FSW. The use of OBCP enhances the on-board autonomy capabilities and increases the robustness to ground stations outages. The OBCP engine which is the core module of OBCP component in the FSW interprets and executes of the procedures based on script language written using a high-level language, possibly compiled, and it is relying on a virtual machine of the OBCP engine. FSW team in KARI has studied OBCP since 2010 as FSW team's internal projects, and made some OBCP engines such as Java KVM, RTCS/C and KKOMA on ERC32 processor target only for study. Recently we have been studying ESA's OBCP standard and implementing Lua and MicroPython on LEON2-FT/AT697F processor target as the OBCP engine. This paper presents the design and implementation of Lua for the OBCP engine on AT697F processor with VxWorks RTOS, and describes the evaluation result and performance of the OBCP engine.