• International journal of advanced smart convergence
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• v.11 no.3
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• pp.23-27
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• 2022

In this paper, we explore a new type of Android evasive malware based on the Sequential Probability Ratio Test (SPRT) that does not perform malicious task when it discerns that dynamic analyzer is input generator. More specifically, a new type of Android evasive malware leverages the intuition that dynamic analyzer provides as many inputs within a certain amount of time as possible to Android apps to be tested, while human users generally provide necessary inputs to Android apps to be used. Under this intuition, it harnesses the SPRT to discern whether dynamic analyzer runs in Android system or not in such a way that the number of inputs per time slot exceeding a preset threshold is regarded as evidence that inputs are provided by dynamic analyzer, expediting the SPRT to decide that dynamic analyzer operates in Android system and evasive malware does not carry out malicious task.

• The Journal of Korean Association of Computer Education
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• v.10 no.5
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• pp.71-79
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• 2007

The purpose of this research is to show that elements of learning information's record(learning time and the score of practice test) have a significant effect on the correctness of decision when they are applied to e-Learning based on CAT with SPRT model. Especially, the score of practice test can be used in the real e-learning environment as its effect showed approximately 90% improvement. Therefore, if we apply learning information's record to SPRT in evaluation, we can evaluate the learner's ability more precisely and quickly, contributing to the enhancement of the individualization of learners. If an algorithm with variables from learning information's record can be developed, a better e-Learning evaluation program will be made in the future.

• The Korean Journal of Applied Statistics
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• v.18 no.1
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• pp.57-66
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• 2005

In this paper, we propose a method to evaluate the solutions of the renewal equations related to SPRT for Erlang distribution. In SPRT, the Average Sample Number(ASN) and type I or type II error probabilities are shown in Fredholm type integral equations. The integral equations are generally solved by the approximation method using Gaussian quadrature. For Erlang distribution, it has been known that the exact solutions of the equations exist. We propose the algorithm to solve the equations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2067-2080
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• 2016

Cooperative spectrum sensing (CSS) for vacant licensed bands is one of the key techniques in cognitive radio networks. Currently, sequential probability ratio test scheme (SPRT) is considered as a powerful soft decision approach to improve the sensing result for CSS. However, SPRT assumes all secondary users (SU) are honest, and thus offering opportunities for malicious SUs to launch the spectrum sensing data falsification attack (SSDF attack). To combat such misbehaved behaviors, recent efforts have been made to trust mechanism. In this paper, we argue that powering SPRT with traditional trust mechanism is not enough. Dynamic SSDF attackers can maintain high trust in an alternant process of submitting honest or false sensing data, resulting in difficultly detecting them. Noting that the trust value of dymamic SSDF attackers behave highly volatile, a novel trusted SPRT scheme (VSPRT) based on volatility decay analysis is proposed in this paper to mitigate the harmful effect of dynamic SSDF attackers in the process of the soft-decision data fusion, and thus improving the accuracy of the final sensing result. Simulation results show that the VSPRT scheme outperforms the conventional SPRT schemes.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.3
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• pp.51-57
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• 2010

Steganography techniques can be used to hide data within digital images with little or no visible change in the perceived appearance of the image. I propose a steganalysis to detecting hidden message in sequential steganography. This paper presents adjusted technique for detecting abrupt jumps in the statistics of the stego signal during steganalysis. The repeated statistical test based on CUSUM-SPRT runs constantly until it reaches decision. In this paper, I deal with a new and improved statistic $g_t$ by computing $S^{t^*}_j$.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.989-992
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• 2005

CAT(Computer Adaptive Testing : 컴퓨터 기반 적응적 검사)는 기존의 종이 시험지에서 이루어지던 시험과 달리 수험자에게 적절한 맞춤식 출제로 보다 정확한 수험자의 능력 판단 및 빠른 수험진행을 가능케 하였다. 기존의 CAT는 많은 인원과 문제가 있어야만 그 결과에 신뢰성이 있다고 알려져 있다. CAT의 대표적인 알고리즘인 SPRT와 EXSPRT-R을 이용하여 10명의 적은 인원으로 JLPT 4급 기출문제를 적용한 실험을 하였다. SPRT 에서는 인원수와, 문제 난이도를 무시한 결과로 인하여 만족 할만한 결과를 얻지 못하였으나, EXSPRT-R의 경우에는 적은 인원에서도 충분히 CAT를 이용할 수 있음을 발견할 수 있었다.

• Korean journal of applied entomology
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• v.48 no.1
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• pp.45-51
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• 2009

This paper presents sequential sampling plans for evaluating the pest density based on complete counts from probe in a rice storage warehouse. Both maize weevil and Indian meal moth population showed negative binomial dispersion patterns in brown rice storage. For cost-effective monitoring and action decision making system, sequential sampling plans by using the sequential probability ratio test (SPRT) were developed for the maize weevil and Indian meal moth in warehouses with 0.8 M/T storage bags. The action threshold for the two insect pests was estimated to 5 insects per kg, which was projected by a matrix model. The results show that, using SPRT methods, managers can make decisions using only 20 probe with a minimum risk of incorrect assessment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.1910-1920
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• 1993

An experimental study to investigate the unconventional chip formation called triangulation of chip in cutting with a SPRT (self-propelled rotary tool) is performed using acoustic emission (AE) signal analysis. In doing that, a quantitative model of the AE RMS signal in triangulation with a SPRT is first developed. The predicted results from this model show good correlation between the AE RMS signal and the general characteristics of triangular chip formation. Then, effects of various process parameters such as cutting conditions (cutting speed, depth of cut, oblique angle and normal rake angle) and the work material properties on the chip formation in cutting with a SPRT are explored. Special attention is paid to the work material properties which are found to have significant effects on triangulation.

• Journal of Korean Society for Quality Management
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• v.24 no.4
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• pp.1-13
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• 1996

The sequential sampling inspection method is an extension of the double-sampling and multiple-sampling methods and its theory is based on the sequential probability ratio test(SPRT). In this paper, the characteristics of SPRT for testing the propotion of defectives are approximated by using the estimated excess over the boundaries. The use of the estimated excess shows good performances in estimating the operating characteristic function and the average sample number of SPRT compared to the method by neglecting the excess. It also makes it possible to determine the boundary values which satisfy the desired error probabilities.

• Nuclear Engineering and Technology
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• v.33 no.5
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• pp.483-497
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• 2001

In this work, a neuro-fuzzy inference system combined with the wavelet denoising, PCA (principal component analysis) and SPRT (sequential probability ratio test) methods is developed to detect the relevant sensor failure using other sensor signals. The wavelet denoising technique is applied to remove noise components in input signals into the neuro-fuzzy system The PCA is used to reduce the dimension of an input space without losing a significant amount of information. The PCA makes easy the selection of the input signals into the neuro-fuzzy system. Also, a lower dimensional input space usually reduces the time necessary to train a neuro-fuzzy system. The parameters of the neuro-fuzzy inference system which estimates the relevant sensor signal are optimized by a genetic algorithm and a least-squares algorithm. The residuals between the estimated signals and the measured signals are used to detect whether the sensors are failed or not. The SPRT is used in this failure detection algorithm. The proposed sensor-monitoring algorithm was verified through applications to the pressurizer water level and the hot-leg flowrate sensors in pressurized water reactors.