• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.1
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• pp.28-37
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• 1993

The future Personal Communication Service(PCS) is the total personal information communication service to satisfy the importance of information in a highly information - oriented society. Compared with the conventional communication method, it is necessary to provide considerable intelligence to the commu- nication network in order to implement the PCS which guarantees the mobility of each individual. Consequen- tly, the PCS needs a fast large database system which stores the information of each individual. To achieve this goal, this paper presents the parallel implementation of deductive database systems as a main - memory database system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5C
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• pp.485-497
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• 2009

In this paper, we described DVB-S2 system for mobility. cross layer coding technique are needed to maintain the performance in deep fading channel. Cross layer coding is divided into two kinds of level. First level is Physical layer coding and, second layer is link layer or upper layer coding. Fixed on DVB-S2 short frame coding method as a physical layer, we simulated the various coding method as an upper layer coding. Furthermore, we analyzed the performance of each coding method on according to mobile vehicle speed, data rate, interleaving memory size, and IP packet size.

• ETRI Journal
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• v.19 no.3
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• pp.186-201
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• 1997

In this paper, a home location register (HLR) for CDMA mobile communication system (CMS) is introduced. It stores the mobile station (MS) subscribers locations and supplementary service information. Call processing procedures for HLR are developed to receive and store subscriber's location coming from mobile exchange (MX) during the location registration, and to transfer subscriber's location and supplementary service information to the MX during the mobile-terminated call setup. For fast call processing by increasing database access speed, a memory-resident database management system is devised. For Easy and secure HLR operation, administration and maintenance functions and overload control mechanisms are implemented. Designed HLR hardware platform is expandable and flexible enough to reallocated software blocks to any subsystems within the platform. It is configurable according to the size of subscribers. An authentication center (AC) is developed on the same platform. It screens the qualified MS from the unqualified. The calls to and from the unqualified MS are rejected in CMS. To authenticate the MS, the AC generates a new authentication parameter called "AUTHR" using shared secret data (SSD) and compared it with the other AUTHR received from the MS. The MC also generates and stores seed keys called "A-keys" which are used to generate SSDs. The HLR requirements, the AC requirements, software architecture, hardware platform, and test results are discussed.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.91-105
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• 2016

Carbon Nanotube Field-Effect Transistors (CNTFETs) have been studied as candidates for post Si CMOS owing to the better electrostatic control and high mobility. To enhance the immunity against short - channel effects (SCEs), the novel channel and gate engineered architectures have been proposed to improve CNTFETs performance. This work presents a comprehensive study of the influence of channel and gate engineering on the CNTFET switching, high frequency and circuit level performance of carbon nanotube field-effect transistors (CNTFETs). At device level, the effects of channel and gate engineering on the switching and high frequency characteristics for CNTFET have been theoretically investigated by using a quantum kinetic model. This model is based on two-dimensional non-equilibrium Green's functions (NEGF) solved self - consistently with Poisson's equations. It is revealed that hetero - material - gate and lightly doped drain and source CNTFET (HMG - LDDS - CNTFET) structure can significantly reduce leakage current, enhance control ability of the gate on channel, improve the switching speed, and is more suitable for use in low power, high frequency circuits. At circuit level, using the HSPICE with look - up table(LUT) based Verilog - A models, the impact of the channel and gate engineering on basic digital circuits (inverter, static random access memory cell) have been investigated systematically. The performance parameters of circuits have been calculated and the optimum metal gate workfunction combinations of ${\Phi}_{M1}/{\Phi}_{M2}$ have been concluded in terms of power consumption, average delay, stability, energy consumption and power - delay product (PDP). In addition, we discuss and compare the CNTFET-based circuit designs of various logic gates, including ternary and binary logic. Simulation results indicate that LDDS - HMG - CNTFET circuits with ternary logic gate design have significantly better performance in comparison with other structures.

• Journal of Advanced Navigation Technology
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• v.11 no.3
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• pp.239-251
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• 2007

This thesis is about the reduction of the power consumption in GPS embedded terminals with periodic position fix to improve the time delay of position determination. In order to improve time delay of position determination during the wireless terminal is powered on, it needs to be set such that it can be periodically recalibrated by the GPS and those recalibrated values need to be saved in the terminal's memory so that it can reduce the time delay from the request of location. By using the trace of the information that's been saved in the terminal's memory, it can be set so that it'll be easier to determine whether the wireless terminal has gone into buildings and have the capability of checking if it has gone into a specific building. Likewise, while the terminal is turned on, in order calibrate the location, it needs to continuously work the GPS engine which leads to a rapid decrease in terminal's idle time. This thesis proposes some solutions regarding these issues - reducing 20 ~ 30% of the battery consumption for GPS visible situation that can occur when the wireless terminal periodically calibrates its location to determine the in-building status, and extending the idle time of the terminal by flexibly using the suggested GPS calibration time method according to wireless terminal's mobility.

• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.415-426
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• 2005

Wireless internet, which becomes a hot social issue, has limitations due to the following characteristics, as different from wired internet. It has low bandwidth, frequent disconnection, low computing power, and small screen in user terminal. Also, it has technical issues to Improve in terms of user mobility, network protocol, security, and etc. Wireless internet server should be scalable to handle a large scale traffic due to rapidly growing users. In this paper, wireless internet proxy server clusters are used for the wireless Internet because their caching, distillation, and clustering functions are helpful to overcome the above limitations and needs. TranSend was proposed as a clustering based wireless internet proxy server but it has disadvantages; 1) its scalability is difficult to achieve because there is no systematic way to do it and 2) its structure is complex because of the inefficient communication structure among modules. In our former research, we proposed the All-in-one structure which can be scalable in a systematic way but it also has disadvantages; 1) data sharing among cache servers is not allowed and 2) its communication structure among modules is complex. In this paper, we proposed its improved scheme which has an efficient communication structure among modules and allows data to be shared among cache servers. We performed experiments using 16 PCs and experimental results show 54.86$\%$ and 4.70$\%$ performance improvement of the proposed system compared to TranSend and All-in-one system respectively Due to data sharing amount cache servers, the proposed scheme has an advantage of keeping a fixed size of the total cache memory regardless of cache server numbers. On the contrary, in All-in-one, the total cache memory size increases proportional to the number of cache servers since each cache server should keep all cache data, respectively.

• Journal of Platform Technology
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• v.11 no.2
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• pp.39-53
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• 2023

Non-installation program (hereinafter referred to as "portable program") is a program that can be used without an installation process, unlike general software. Since there is no separate installation process, portable programs have high mobility and are used in various ways. For example, when initial setup of multiple PCs is required, a portable program can be stored on one USB drive to perform initial setup. Alternatively, when a problem occurs with the PC and it is difficult to boot normally, Windows PE can be configured on the USB drive and portable programs can be stored for PC recovery. And the portable program does not directly affect PC settings, such as changing registry values, and does not leave a trace. This means that the portable program has high security. If a portable program is deleted after using it, it is difficult to analyze behavior in a general way. If a user used a portable program for malicious behavior, analysis in a general way has limitations in collecting evidence. Therefore, portable programs must have a new way of behavioral analysis that is different from ordinary installation software. In this paper, after installing the Windows 10 operating system on a virtual machine, we proceed with the scenario with a portable program of Opera and Notepad++. And we analyze this in various ways such as file analysis of the operating system and memory forensics, collect information such as program execution time and frequency, and conduct specific behavioral analysis of user.

• Journal of Home Health Care Nursing
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• v.30 no.3
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• pp.252-263
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• 2023

Purpose: To assess the feasibility, safety, and preliminary estimates of effectiveness of Tai Chi on the functional outcomes of older adults in the community. Methods: This was a mixed-method study that employed a single-group repeated measure design and in-depth interviews. Nine older adults were recruited from the community were recruited to participate in a Tai Chi program, conducted twice weekly for 6 months. Research outcomes included physical function, cognitive function, and quality of life, measured at intervals of 3 and 6 months. Findings: Tai Chi exercises were gradually conducted based on the health status of the older adults. All participants actively participated in the program with an average attendance of 90%. Consequently, the participants showed significant improvements in mobility and their memory recall ability at both 3 and 6 months. Additionally, the results of the Stroop test exhibited improvement 3 months after the commencement of the study program. Quality of life of the participants improved according to the mild cognitive impairment questionnaire, but it did not show significant improvement in health-related quality of life. Conclusion: The Tai Chi exercise program was a safe and, feasible program to improve the physical function, cognitive function, quality of life among the older adults in the community.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2A
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• pp.90-97
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• 2005

Generally, DAB systems are divided into two categories, a stand-alone type and a PC/PDA-based type. The PC/PDA-based type has less mobility comparing to the stand-alone type, nevertheless, it has the advantage of using memory, audio/video decoder, or other resources of PC/PDA. The DAB receiver implemented in this paper is a PC-based receiver system employing USB interface. The USB interface bridge is designed using FPGA and EZ-USB development kit and the implemented DAB receiver adopts the bridge and makes use of the stand-alone typed DRK-026 receiver for experiments. The USB interface bridge transforms serial data into USB packets and all of related signals are controlled by hardware logics. The operation of the implemented DAB receiver is verified by sending audio data into the PC for decoding through USB interface bridge.

• Journal of IKEEE
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• v.26 no.3
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• pp.364-372
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• 2022

This paper proposes the design and implementation results for human and object classification systems utilizing frequency modulated continuous wave (FMCW) radar sensor. Such a system requires the process of radar sensor signal processing for multi-target detection and the process of deep learning for the classification of human and object. Since deep learning requires such a great amount of computation and data processing, the lightweight process is utmost essential. Therefore, binary neural network (BNN) structure was adopted, operating convolution neural network (CNN) computation in a binary condition. In addition, for the real-time operation, a hardware accelerator was implemented and verified via FPGA platform. Based on performance evaluation and verified results, it is confirmed that the accuracy for multi-target classification of 90.5%, reduced memory usage by 96.87% compared to CNN and the run time of 5ms are achieved.