• Proceedings of the Korean Statistical Society Conference
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• 2001.11a
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• pp.185-189
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• 2001

In this paper, we consider the problem of testing for parameter changes in time series models based on a sequential test. Although the test procedure is well-established for the mean and variance change, a general parameter case has not been discussed in the literature. Therefore, we develop a sequential test for parameter changes in a more general framework.

• Journal of Applied Reliability
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• v.3 no.2
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• pp.137-143
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• 2003

Sequential test plans are characterized by decision rules for accepting or rejecting compliance, or continuing the test at my test time. They are determined by selected values of risks and discrimination ratio. The sequential test plans in the international standard such as MIL-HDBK-781A are based on the assumption that the underlying distribution of times between failures is exponential. In this paper, sequential test plans are extended to the Weibull distribution case. Simulation studies are performed to examine the reasonability in this extension.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6C
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• pp.532-540
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• 2005

In this paper, a sequential detection scheme is proposed as a combination of a novel weak-signal and a locally optimum(LO) detection schemes. In Part 1, we propose a novel sequential detection scheme for weak signals and show some interesting threshold properties and examples. In Part 2, the performance of the proposed sequential detection scheme is compared with that of the fixed sample size(FSS) test, sequential probability ratio test (SPRT), and truncated sequential probability ratio test(TSPRT).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10C
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• pp.1027-1035
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• 2005

In this paper, the performance of the sequential detection scheme proposed in Part 1 is compared with that of the fixed sample size (FSS) test, sequential probability ratio test (SPRT), and truncated sequential probability ratio test (TSPRT). The proposed sequential detection scheme requires less complexity and, in most cases, smaller sample size than the SPRT. It is also observed that the proposed sequential detection scheme has always lower complexity and smaller sample size than the FSS test and TSPRT.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.9
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• pp.38-48
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• 1998

Generating test patterns for asynchronous sequential circuits remains to be a very difficult problem. There are few algorithms for this problem, and previous works cut feedback loops, and insert synchronous flip-flops in the feedback loops during ATPG. The conventional algorithms are similar to the algorithms for synchronous sequential circuits. This means that the conventional algorithms generate test patterns by modeling asynchronous sequential circuits as synchronous sequential circuits. So, test patterns generated by those algorithms nay not detect target faults when the test patterns are applied to the asynchronous sequential circuit under test. In this paper an algorithm is presented to generate test patterns for asynchronous sequential circuits. Test patterns generated by the algorithm can detect target faults for asynchronous sequential circuits with the minimal possibility of critical race problem and oscillation. And it is guaranteed that the test patterns generated by the algorithm will detect target faults.

• Journal of Communications and Networks
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• v.11 no.2
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• pp.122-133
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• 2009

As wireless spectrum resources become more scarce while some portions of frequency bands suffer from low utilization, the design of cognitive radio (CR) has recently been urged, which allows opportunistic usage of licensed bands for secondary users without interference with primary users. Spectrum sensing is fundamental for a secondary user to find a specific available spectrum hole. Cooperative spectrum sensing is more accurate and more widely used since it obtains helpful reports from nodes in different locations. However, if some nodes are compromised and report false sensing data to the fusion center on purpose, the accuracy of decisions made by the fusion center can be heavily impaired. Weighted sequential probability ratio test (WSPRT), based on a credit evaluation system to restrict damage caused by malicious nodes, was proposed to address such a spectrum sensing data falsification (SSDF) attack at the price of introducing four times more sampling numbers. In this paper, we propose two new schemes, named enhanced weighted sequential probability ratio test (EWSPRT) and enhanced weighted sequential zero/one test (EWSZOT), which are robust against SSDF attack. By incorporating a new weight module and a new test module, both schemes have much less sampling numbers than WSPRT. Simulation results show that when holding comparable error rates, the numbers of EWSPRT and EWSZOT are 40% and 75% lower than WSPRT, respectively. We also provide theoretical analysis models to support the performance improvement estimates of the new schemes.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.3
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• pp.1-6
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• 1976

In this paper, a method of test pattern generation for the functional failure in both combinational and sequentlal logic networks by using exterded Boole an difference is proposed. The proposed technique provides a systematic approach for the test pattern generation procedure by computing Boolean difference of the Boolean function that represents the Logic network for which the test patterns are to be generated. The computer experimental results show that the proposed method is suitable for both combinational and asynchronous sequential logic networks. Suitable models of clocked flip flops may make it possible for one to extend this method to synchronous sequential logic networks.

• Journal of the Korean Statistical Society
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• v.1 no.1
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• pp.11-17
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• 1973

A class of sequential binomial tests and a sequential rank test can be applied for testing two treatments when subjects are paired in many-to-one ratio. The efficiency of each test is examined in terms of the average sample number. The binomial tests are much easier and more convenient to apply than the rank test not as efficient. Within the class of binomial test, the median test appears to be the most efficient is general.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1507-1511
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• 1987

This paper proposes a NAND-NAND logic sequential Programmable Logic Array (PLA) using CMOS technology, and test generation methods about stuck-open faults. By using LSSD (Level Sensitive Scan Design) method instead of Flip-Flops in Sequential PLA, the complex test problems of sequential logic are simplified. After generating the test sets using connection graph, regular test sequences and all transistor faults detection method in PLA are proposed. Finally, by programming these algorithms in PASCAL at VAX 8700 and adopting these to pratical CMOS Sequential PLA circuits, we proved the effectiveness of this design.

• Journal of the Korean Statistical Society
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• v.30 no.4
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• pp.679-691
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• 2001

Two truncated sequential tests are developed for the two-sample scale problem based on the usual Wilcoxon rank-sum statistic for two different dispersion indices - absolute median deviations, when the medians of the two populations X and Y are equal or known and sums of squared mean deviations, when the medians are either unknown or unequal. The first test is briefly called SWAMD test and the second SWSMD test. For the SWAMD test, the percentile points for both the one-sided and two-sided alternatives, (equation omitted) have been found by Wiener approximation and their values computed for a range of values of a and N; analytical expression for the power function has been derived through Wiener process and its performance studied for various sequential designs for exponential distribution. This test has been illustrated by a numerical example. All the results of the SWAMD test, being directly applicable to the SWSMD test, are not dealt with separately Both the tests are compared and their suitable applications indicated.