• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.343-356
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• 1991

An efficient real-time implementation of digital filtering algorithms using a multiprocessor system in a ring network is investigated. The development time and cost for implementing a high speed signal processing system can be considerably reduced because algorithm are implemented in software using commercially available digital signal processors. This method is based on a parallel block processing approach, where a continuously supplied input data is divided into blocks, and the blocks are processed concurrently by being assigned to each processor in the system. This approach not only requires a simple interconnection network but also reduces the number of communications among the processors very much. The data dependency of the blocks to be processed concurrently brings on dependency problems between the processors in the system. A systematic scheduling method has been developed by using a processors which can be used efficiently, the methods for solving dependency problems between the processors are investigated. Implementation procedures and results for FIR, recursive (IIR), and adaptive filtering algorithms are illustrated.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.7
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• pp.115-122
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• 1995

This paper presents the simulation environment that verifies whether a new microprocessor described with HDL is compatible with MS-DOS. The phrase 'compatible with MS-DOS' means that the microprocessor can execute MS-DOS without any modification of MS-DOS's binary code. The proposed verification environment consists of HDL simulator and user interface module. And the communications between them are performed by using sockets which UNIXprovide. The HDL simulator is equipped with several functions, which use PLI to emulate ROM-BIOS facilities. The ROM-BIOS emulation routine is described by using these functions. User interface module utilizes S/MOTIF and participates in emulating PC monitor and keyboard. The verification environment is tested by executing the MS-DOS commands (DIR, FORMAT, DATE, TIME etc.) with the HDL model of microprocessor, and the display of user interface module verifies that the environment works correctly. In this paper, the method of constructing the verification environment is presented, and the simulation results are summarized.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.99-104
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• 1998

It is a good flexibility of bending body and non-interaction of outer bodies for slit antenna to be being studied and developed in this paper. The characteristics of leaked EM waves in slit transmission line are applied to antennas of tele-communication systems. The computer simulations using a special software adapt to design a new slit antenna, and to apply to tele-communications systems with frequencies of land mobile communication (800-900MHz). The good results of which reflection coefficient 511 is 0.21 and directivity is 2.9 and band-widths are 1.5MHz in 851MHz are shown.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.38-46
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• 1996

The purpose of this study is to develop the miniaturized duplexer filter for mobile communications using high dielectric constant (${\varepsilon}$r > 100, 180) ceramic resonators. Duplexer filter was ocmposed of ceramic resonators which has been developed using BNT system and SCT system, respectively. Developed duplexer filter was formed to have Tx frequency band at 836.5 (($\pm$12.5)MHz and Rx frequency band at 881.5 ($\pm$12.5)MHz. Insertion loss at Tx frequency band was 1.41dB and 1.46dB, insertion loss at Rx frequency band was 3.49dB and 3.65dB, respectively. Especially, duplexer filters using dielectric cermaics with ${\varepsilon}$r = 180 were 8% smaller than commercially manufactured duplexer filters using dielectric ceramics with ${\varepsilon}$r = 90 by murata.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.4
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• pp.27-36
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• 1993

This paper proposes a shortest path allocation algorithm over the processors on the hypercube system based on the message passing techniques with the optimized module allocation. On multiprocessor systems, how to divide one task into multiple tasks efficiently is an important issue due to the hardness of the life cycle estimation of each process. To solve the life cycle discrepancies, the appropriate task assignment to each processor and the flexible communications among the processors are indispensible. With the concurrent program execution on hypercube systems, each process communicaties to others with the method of message passing. And, each processor has its own memory. The proposed algorithm generates a callable tree out of the module, assigns the weight factors, constructs the allocation graph, finds the shortest path allocation tree, and maps them with hypercube.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.12
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• pp.1903-1909
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• 1989

In this paper, the mobile communication CH simulator is implemented in the baseband, using the Digital Signal Processor(TMS320C25), A/D and D/A converters. The Rayleigh CH is modeled by shaping the random noise source power spectrum. The statistical characteristics(Level Crossing Rate, Cumulative distribution Function, Probability Density Function) and the received fading signal's power's spectrum is observed when the doppler frequency is varied according to the variation of the vehicular velocity at the 222MHz band. And also the BER is measured when the baseband mobile CH simulator is applied to the GMSK(Gaussian Minimum Shift Keying` transmission rate: 16kbps, Bb T=0.25) modulator. The results shows the similar characteristics to be compared with the theoritically derived BER values of the discriminator type GMSK detection.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.11
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• pp.1455-1463
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• 1995

A new automatic tracking & recognition algorithm which decides the opening & the closing states of subject's eye and isn't affected by the subject's background is proposed. And it was tested in circumstances in which subject's background was not restricted using the developed system, ATRS(Automatic Tracking & Recognition System). The significant characteristic of the ATRS is new movement detection of object that is a body in motion with accelated velocity and it doesn't need any extra hardware except a formal CCD camera and an image grabber but it works so well and so fast. The ATRS would be particularly well suited to a way of communications of patients in a hospital, who can not communicate otherwise.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.3
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• pp.370-375
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• 1987

In this study, the Rayleigh fast fading simualtors encountered in channel modelling of mobile radio have been implemented and evaluated. Two models used for the fading environment were frequency composition of phase modulated signals and shaping spectrum of noise sources with filters. The spectrum chosen for our purpose is appropriate to an omnidirectional antenna. From results of the experiment with various parameters, we have obtained satisfying results which are closely agreed to theoretical values.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.14-24
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• 2006

The terrestrial-DMB (T-DMB) provides one-way broadcasting service in intial phase and two-way interactive data services through a return channel of mobile communications network are commercialized recently. The possible evolution of the T-DMB will be fully convergence between the T-DMB and other communication services such as telematics, RFID and so on. From this evolution point of view, a framework should be defined for supporting telematics and RFID applications on T-BMB platform. In this paper, we propose an integrated service model that could support RFID application services on the interactive T-DMB. To realize the model, we design a service scenario, a network reference model, functionalities of each entity, a data transmission mechanism messages, and coding rules. The service model could allow users to support the identical RFID application services over the T-DMB network even if T-DMB terminal doesn't have RFID reader capability. In addition, in the case for providing the interactive TTI(Traffic and Travel Information)service, users could utilize the current location based RFID application service using by the TPEG-Location application that forms the basis of user location referencing. The messages structure is designed by following TPEG standardization

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1047-1056
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• 2007

In this paper, we analyze the performance of the encoding and the modulation processes in the downlink and uplink of the EPCglobal Gen-2 system through the analysis and simulation. Furthermore, the synchronization issues on time and frequency domain and the preamble architecture are evaluated. By incorporating the encoding and the modulation technigue in the downlink and uplink, we assess the performance of the EPCglobal Gen-2 system. We also introduce the encoding and backscatter modulation process as well as the BER performance of FM0 code. In addition, the importance and the role of the frequency and time synchronization, such as the preamble and frame synchronization are explained. Through the simulation in the uplink on the detection probability through preamble, we find that the detection probability approaches 1 for 13 dB $E_b/N_0$.