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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 17, Issue 12 - Dec 1992
Volume 17, Issue 11 - Nov 1992
Volume 17, Issue 10 - Oct 1992
Volume 17, Issue 9 - Sep 1992
Volume 17, Issue 8 - Aug 1992
Volume 17, Issue 7 - Jul 1992
Volume 17, Issue 6 - Jun 1992
Volume 17, Issue 5 - May 1992
Volume 17, Issue 4 - Apr 1992
Volume 17, Issue 3 - Mar 1992
Volume 17, Issue 2 - Feb 1992
Volume 17, Issue 1 - Jan 1992
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A Design Method of Wide-band Filter with Optical Fiber and Directional Coupler
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 539~547
Considering the field of high frequency or broad-band signal filtering with high speed, we pro-pose optical fiber filters which consist of directional couplers and optical fiber delay elements. Fiber delay line signal processor Is operated with Incoherent optical carrier because of Its simplicity. Due to the characteristics of the directional coupler which Is basic element of optical fiber filter a new design method which Is different from that of usual digital filter is required. By considering the characteristics of directional coupler and in order to make good use of the optical signal energy, we have given the design formulae and the conditions of optical fiber filters for the direct and the lattice form.
Implementation of X.25 for the TDX-10 Packet Switching
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 548~557
This paper presents how X.25 state machines are defined and procedures are implemented Into the TDI-10 switching system, which Is being developed as an ISDN exchange in Korea.Packet switching is an in important aspect of I SDN. Packet swichedd services in ISDN are defined by X.:31, which provides for the use X.f,j over ISDN B and D-channels between a user and an X.25packet handler. To implement X.2E into an ISDN exchange which Includes a packet handler, X.25state machines and procedures should be adj usted within the ISDN exchange.
A Protocol Validation by Extended Circular Exploration
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 558~571
In this paper, we propose an improved method of state exploration called the extended circular exploration (ECE) for the efficiency of state exploration and the reduction of explosively growing state. The ECE does not need to explore all the reachable global states, and It can be applied to JV(
2) -party protocol with alternative routes, i.e., it is applicable to the protocol In which adaptiverouting mechanism can be performed. The ECE eliminates a restriction of topology of the conventional circular exploration(CE) by exploring only those global states which are reachable, provided that the participant processes of any group of transitions proceed at the same speed, and that they can be formed as a cycle. Thus the state space explored if not exhaustive. The algorithm presented can detect deadlock error and unspecified reception error It requires storage space and /or execution time much less than those of the conventional perturbation(CP) . It might be used for a solution of the N-process collision and the interference mechanism.
A Study on the Implemanation of IF Stage for Reducing Random Noise in the Mobile Communications
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 572~579
In this thesis, feedback circuit and FM detector applied to superheterodyne receiver to extract audio signal without random noise Is implemented. The feedback loop circuit converts 45MHz received signal to 4SiKHz If signal containing mess-age without random noise. Also the feedback loop provides the End local frequency, so narrowband BPF which is containing maximum Doppler frequency without message Is needed. Finally, quadrature FM detector extract audio signal by synthesis o350" shifted signal and ampli-tude limited signal. RSSI characteristics is measured and audio characteristics Is compared with existing If moduleodule
Microwave Absorbing Characteristics of Silicon carbide-ferrite surface Films Produced by Plasma-spraying(I)
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 580~588
Plasma-spraying was conducted to produced the microwave absorbing surface films on the alumi-num-alloy used for the fuselage to protect the aircraft against the RADAR detction. The surface films were produced by plasma-splaying the mecharucally mixed composite powders of the silicon carblde and Ni-Zn ferrite. This M /W absorbers were designed experimentally and fabricated trialty, as a result of which the rolative frequency bandwidth of 7.6 to 8.4% were obtained under the tolerance limits of the re-flection coefficients lower than -6dB(absorption ratio 75%), and the maximum absorption thickness becomes 0.5 to 0.5.imm, which Is much thinner than that of the conventional ones
A Study on Minimization of Multiple-Valued Logic Funcitons using M-AND, M-OR, NOT Operators
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 589~594
This paper offers the simplification method of Multiple-Valued logic function based on M-AND,M-OR, NOT operation presented by Lukasiewicz. First in performing the simplification the result is different by the method to arrange Cube, the method to find the most effective adjacent term if, most of all, important in simplification. According to this method, the two-variable multiple-valued logic function given by truth table is decomposed. The simplification method in this paper proves that the number of devices and cost is considerably reduced comparing with the existing method 141 to realize the same logic functions.
A Study on the bounding method for computing the reliability of communication networks
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 595~603
It has been establisued that the reliability of communication networks is NP hard problem owing to computationally and complexity as the number of componeuts is Increased in large networks. This paper proposed an algorithm for determining upper and lower bounds In the reliability of source-to-terminal in communication networks to solve this problem. The evaluation method follows the next procedures. First, minimal pathset and minimal cut set are serched. Second, it is sorted that the number of components is the same events and the reliability bounds Is evaluated by the section function to extract common variable. The performance of proposed algorithm is also estimate(1 as compared to the reliability of Esary-Proschan, Shogan and Copal.
Overlapping Wavelet Transform
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 604~612
OWT is a tool for block transform coding with wavelet basis functions that overlap adjacent blocks. The OWT can reduce the block effect. Without increasing the transmission data in this paper transform matrix of OWT Is presented. Some simulation results show that performances are early same to BCT, but block effect is reduced to very low level
Real-time Implementation of OptoFuzzy Inference System
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 613~620
Recently, there are lots of research work on fuzzy Information theory for many practlcal applications. As the fuzzy control systems become to be sophisticated, they demand more fuzzy parameters, membership functions and fuzzy Inference rules. Eventually, they need effective parallel computing architectures to implement those complex fuzzy inference rules. In this paper, a optical fuzzy Inference system based on 2-D spatial light modulator and digital image board Is Implemented as a new approach for real-time parallel fuzzy computing system. From its good experimental results on the practical fuzzy airconditioner system, a new real-time Opto Fuzzy Inference system Is suggested
Progressive Image Transmission by Hierarchical Images of arbitrary Ratio
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 621~628
This paper proposes a progressive Image transmission method with a variable magnification hierarchical structure for image processing system. As Introduced in the literature, the progressive image transmission method, uses a fixed magnification rates of either 4 or 1/4. Thus, a sudden in-crease In resolution Is obtained due to a sudden Increase in information. By adapting a variable magnification hlerarchical structure In this research, a gradual increase in resolution Is possible by slowly inrireasing information between hierarchical levels. The simulation results show that a 5.7dB SNR improvemr'nt Is obtained with an Improved compression rate by 0.7 Ult /pel compare to the LP method. It also gives about 1 dB SNR improvement compare to the PCS method at intermediate hierarchical levels.
An Encryption Key Distribution System in LAN Environment Using Time Quantum
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 6, 1992, Pages 629~639
This paper examines the security vulnerability, demanded service, layering consideration for local area networks(LANs), and proposes a new key distribution system suitable to local area networks. the new key distribution system Is applicable to time quantum in encrytion key and then the time used arid the quantity of encryption message using the encryption key are limited. A system suggested in this paper can achive some higher concurrency of key and authentication of the opposite party. Even through a encryption key expose by reason of wiretapping of a frame unit, It has achived some more security and safety, because the contens of all traffic messages are not known.