• Journal of KIISE
• /
• v.43 no.10
• /
• pp.1154-1164
• /
• 2016

To prevent the use of one's smartphone by another user, the authentication checks the owner in several ways. However, whenever the owner does use his/her smartphone, this authentication requires an unnecessary action, and sometimes he/she finally decides not to use an authentication method. This can cause a fatal problem in the smartphone's security. We propose a sustainable android platform-based authentication mode to solve this security issue and to facilitate secure authentication. In the proposed model, a smartphone identifies the current situation and then performs the authentication. In order to define the risk of the situation, we conducted a survey and analyzed the survey results by age, location, behavior, etc. Finally, a demonstration program was implemented to show the relationship between risk and security authentication methods.

• KIPS Transactions on Software and Data Engineering
• /
• v.6 no.4
• /
• pp.185-192
• /
• 2017

In various fields of science, 2-dimensional array data is being generated actively as a result of measurements and simulations. Although various query processing techniques for array data are being studied, the problem of finding similar regions, whose sizes are not known in advance, in 2-dimensional array has not been addressed yet. Therefore, in this paper, we propose an efficient method for finding regions with similar element values, whose size is larger than a user-specified value, for a given 2-dimensional array data. The proposed method, for each pair of elements in the array, expands the corresponding two regions, whose initial size is 1, along the right and down direction in stages, keeping the shape of the two regions the same. If the difference between the elements values in the two regions becomes larger than a user-specified value, the proposed method stops the expansion. Consequently, the proposed method can find similar regions efficiently by accessing only those parts that are likely to be similar regions. Through theoretical analysis and various experiments, we show that the proposed method can find similar regions very efficiently.

• Smart Media Journal
• /
• v.5 no.4
• /
• pp.18-25
• /
• 2016

Virtualized hardware resources provides efficiency in use and easy of management. Based on the benefits, virtualization techniques are used to build large server clusters and cloud systems. The performance of a virtualized system is significantly affected by the virtual machine scheduler. However, the existing virtual machine scheduler have a problem in that the I/O response is reduced in accordance with the scheduling delay becomes longer. In this paper, we introduce the Loan/Redemption mechanism of a virtual machine scheduler in order to improve the responsiveness to I/O events. The proposed scheme gives additional credits for to virtual machines and classifies the task characteristics of each virtual machine by analyzing the credit consumption pattern. When an I/O event arrives, the scheduling priority of a virtual machine is temporally increased based on the analysis. The evaluation based on the implementation shows that the proposed scheme improves the I/O response 60% and bandwidth of virtual machines 62% compared to those of the existing virtual machine scheduler.

• Journal of the Institute of Convergence Signal Processing
• /
• v.10 no.1
• /
• pp.86-92
• /
• 2009

As increasing of using induction motors, the induction motors faults cause serious damage to the industry. Therefore to find out faults of induction motor is recognized as important problem awaiting solution. But to make matters worse, the faults of induction motors often progress through long time. It means that early diagnosis is very important. Many researches have been progressed and general method of diagnosis is using vibration sensor to diagnose fault of induction motor. However, although it is reliability technique, it demands high price and it is difficult to use. This paper presents an implementation of technique for fault diagnosis of induction motor using wavelet transform based stator current and it is composed with algorithm that decides whether fault existence or not using C++ based on windows software. The algorithm will be accomplished in real-time using current data acquisition board and PC automatically with Neural Network algorithm.

• Journal of KIISE:Software and Applications
• /
• v.33 no.9
• /
• pp.741-750
• /
• 2006

In this paper, we propose a method for reconstructing a 3D object (or a set of objects) from a 2D drawing provided by a designer. The input 2D drawing consists of a set of contours that may partially overlap each other or be self-overlapping. Accordingly, the resulting 3D object(s) may occlude each other or be self-occluding. The proposed method is composed of three major steps: 2D contour analysis, 3D skeleton computation, and 3D object construction. Our main contribution is to compute the 3D skeleton from the self-intersecting 2D counterpart. We formulate the 3D skeleton construction problem as a sequence of optimization problems, to shape the skeleton and place it in the 3D space while satisfying C1-continuity and intersection-free conditions. Our method is mainly for a silhouette-based sketching interface for the design of 3D objects including self-intersecting objects.

• Journal of Korean Society for Geospatial Information Science
• /
• v.11 no.3 s.26
• /
• pp.55-63
• /
• 2003

Korean cadastral system is primarily based on the graphical maps, thus, map reproduction by excessive shrinkage or extension, map mishandling and imperfection of surveying techniques have created cadastral non-coincident areas, which caused public distrust as well as considerable difficulties in land administration and policy making. Therefore, in this study, the methodologies for the resolution of the non-coincident problem are presented by means of a comparative analysis between cases of the non-coincident areas. The non-coincidence caused by the mismatch of parcel boundaries can be settled by introducing a coordinate-based system namely ${\ulcorner}$Integrated Land Information System${\lrcorner}$, meanwhile, those by other reasons can be done by establishing and executing a plan that can deliver the unification of the cadasoal and the land registration systems. Governmental intention and budgetary measures for securing the project expenses are essential to make this feasible. If the comprehensive improvement project is completed, the cadastral registers that define the parcel boundary, area and ownership will recover public confidence, which in turn secures land owners' rights by promoting land markets and stabilizing land prices.

• The Journal of Korean Medicine
• /
• v.25 no.3
• /
• pp.78-89
• /
• 2004

Background : A report published by the National Institute of Toxicological Research (NITR) in January 2004 about toxic hepatitis in Korea contained the result of analysis on 55 cases of severe toxic hepatitis from 7 university hospitals for 8 months. NITR claimed that the extrapolated annual frequency of severe toxic hepatitis in Korea was 1904 cases per year. They also claimed that the most frequent etiology of severe toxic hepatitis were herbal medications and similar plant preparations (61.7%), contrasted with traditional therapeutic preparations and healthy foods (29.1%). I have investigated that report to be certain of the result because it is a very important subject for public health and society in Korea. Results : The NITR report has too many problems to have faith in its results. They include the following: 1. The report uses only 55 cases to estimate annual prevalence rate of severe toxic hepatitis in Korea. 2. There was a large regional preponderancy in the NITR report (2 cases in Seoul from a population of 10.17 million, 19 cases in Gwangju from a population of 1.4 million) 3. There was another preponderancy that selected much fewer cases caused by western medication (9.1%) than other reasons. 4. The NITR report used a modified scale than that officially recognized to diagnose toxic hepatitis. 5. There was a mistake using the scale to adapt the right indications. 6. They collected cases before beginning the study, although it was a prospective study. There was also not any questionnaire or other materials concerned with alcohol, drugs, or history of past liver disease. Conclusions : NITR is one of the important official arms of the government of Korea. Nevertheless, there is a severe problem in validity because of selection bias, uncertain accuracy, and insufficiency of raw materials in the report. Therefore it seems incorrect to generalize the results of the report and there is a lack of confidence in it as a national study publishing by the NITR.

• The KSFM Journal of Fluid Machinery
• /
• v.13 no.5
• /
• pp.43-53
• /
• 2010

This study investigates a design optimization of a rotating two-pass rectangular cooling channel with staggered arrays of pin-fins. The radial basis neural network method is used as an optimization technique with Reynolds-averaged Navier-Stokes analysis of fluid flow and heat transfer with shear stress transport turbulent model. The ratio of the diameter to height of the pin-fins and the ratio of the streamwise spacing between the pin-fins to height of the pin-fin are selected as design variables. The optimization problem has been defined as a minimization of the objective function, which is defined as a linear combination of heat transfer related term and friction loss related term with a weighting factor. Results are presented for streamlines, velocity vector fields, and contours of Nusselt numbers, friction coefficients, and turbulent kinetic energy. These results show how fluid flow in a two-pass square cooling channel evolves a converted secondary flows due to Coriolis force, staggered arrays of pin-fins, and a $180^{\circ}$ turn region. These results describe how the fluid flow affects surface heat transfer. The Coriolis force induces heat transfer discrepancy between leading and trailing surfaces, having higher Nusselt number on the leading surface in the second pass while having lower Nusselt number on the trailing surface. Dean vortices generated in $180^{\circ}$ turn region augment heat transfer in the turning region and in the upstream region of the second pass. As the result of optimization, in comparison with the reference geometry, thermal performance of the optimum geometry shows the improvement by 30.5%. Through the optimization, the diameter of pin-fin increased by 14.9% and the streamwise distance between pin-fins increased by 32.1%. And, the value of objective function decreased by 18.1%.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.21 no.2
• /
• pp.171-177
• /
• 2011

Accuracy and computing time are considerable issues in machine learning. In general, the computing time for data analysis is increased in proportion to the size of given data. So, we need a sampling approach to reduce the size of training data. But, the accuracy of constructed model is decreased by going down the data size simultaneously. To solve this problem, we propose a new statistical sampling method having similar performance to the total data. We suggest a rule to select optimal sampling techniques according to given data structure. This paper shows a sampling method for reducing computing time with keeping the most of accuracy using cluster sampling, stratified sampling, and systematic sampling. We verify improved performance of proposed method by accuracy and computing time between sample data and total data using objective machine learning data sets.

• The Korean Journal of Pain
• /
• v.28 no.3
• /
• pp.185-192
• /
• 2015

Background: Neuropathic pain is a global clinical problem; nevertheless, nerve injury treatment methods remain limited. Olanzapine has antinociceptive and anti-nueropathic properties; however, its preventive effects have not been assessed in nerve injury models. Methods: We prepared a partial sciatic nerve ligation (Seltzer model) or sham-operated model in male Sprague-Dawley rats under isoflurane anesthesia. In a pre-treatment study, we administered olanzapine (10 mg/kg) intraperitoneally 1 h before nerve ligation. In post-treatment and dose-dependent studies, we injected 3 different doses of olanzapine intraperitoneally 1 h after nerve ligation. Mechanical allodynia was measured before and 7 days after surgery. Immunohistochemical analysis using anti-Iba-1 antibody was used to assess the effect of olanzapine at the spinal level. Results: In the pre-treatment study, median withdrawal thresholds of the normal saline groups were significantly lower than those of the sham-operated groups; however, those of the olanzapine (10 mg/kg) and sham-operated groups were not different. In the post-treatment and dose-dependent studies, the median withdrawal thresholds of the olanzapine (2.5 mg/kg) and normal saline groups were not different; however, those of the olanzapine (10 and 50 mg/kg) groups were significantly higher than those of the normal saline groups. Olanzapine did not have a significant effect on the density of Iba-1 staining. Conclusions: Olanzapine attenuated mechanical allodynia dose-dependently in the Seltzer model. This anti-allodynic effect of olanzapine was observed even when injected 1 h after nerve ligation. This effect of olanzapine appeared to be unrelated to microglia activation in the ipsilateral dorsal horn of the lumbar spinal cord.