• The Journal of the Acoustical Society of Korea
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• v.22 no.1E
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• pp.26-32
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• 2003

We propose new time-frequency (TF) tools for analyzing linear time-varying (LTV) systems and nonstationary random processes showing hyperbolic TF structure. Obtained through hyperbolic warping the narrowband Weyl symbol (WS) and spreading function (SF) in frequency, the new TF tools are useful for analyzing LTV systems and random processes characterized by hyperbolic time shifts. This new TF symbol, called the hyperbolic WS, satisfies the hyperbolic time-shift covariance and scale covariance properties, and is useful in wideband signal analysis. Using the new, hyperbolic time-shift covariant WS and 2-D TF kernels, we provide a formulation for the hyperbolic time-shift covariant TF symbols, which are 2-D smoothed versions of the hyperbolic WS. We also propose a new interpretation of linear signal transformations as weighted superposition of hyperbolic time shifted and scale changed versions of the signal. Application examples in signal analysis and detection demonstrate the advantages of our new results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.6
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• pp.1365-1376
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• 1997

In this paper, we designed real time mechanism control language and proposed execution time analysis technique. It was impossible to handle real-time mechanism control programs like programmable controller, numerical controller, distributed control system and robot controller with general purpose programming languages and operating systems because they have to process electric signals generated by thousands of sensors at the same at the same time and in real time. So we made it possible to predict plausibility of time constraint constructs of tiem constraint construct of a real time application program at compilation time by adding time constraint constructs and mechanism synchronization structure to conditional statement and iteration statement of a programming language and developing execution time analysis technique.

• Journal of Sensor Science and Technology
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• v.15 no.6
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• pp.433-441
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• 2006

Because of the low power and low rate of a sensor network, outlier is frequently occurred in the time series data of sensor network. In this paper, we suggest periodic pattern analysis that is applied to the time series data of sensor network and predict outlier that exist in the time series data of sensor network. A periodic pattern is minimum period of time in which trend of values in data is appeared continuous and repeated. In this paper, a quantization and smoothing is applied to the time series data in order to analyze the periodic pattern and the fluctuation of each adjacent value in the smoothed data is measured to be modified to a simple data. Then, the periodic pattern is abstracted from the modified simple data, and the time series data is restructured according to the periods to produce periodic pattern data. In the experiment, the machine learning is applied to the periodic pattern data to predict outlier to see the results. The characteristics of analysis of the periodic pattern in this paper is not analyzing the periods according to the size of value of data but to analyze time periods according to the fluctuation of the value of data. Therefore analysis of periodic pattern is robust to outlier. Also it is possible to express values of time attribute as values in time period by restructuring the time series data into periodic pattern. Thus, it is possible to use time attribute even in the general machine learning algorithm in which the time series data is not possible to be learned.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.305-311
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• 2019

In this study, present the most useful delay scan time by statistical analysis of SUVm data for 30 suspected pancreatic cancer patients. Two statistical analysis and a mathematical model was applied to the theoretical formula by glucose and insulin mechanics, and a mathematical model was created. Statistical analysis was performed via Metlab p/g. Optimal delay scan time was suggested by Metlab p/g for the change of SUV value over time.In this study, for diagnosis pancreatic cancer by dual time point PET/CT, propose optimal delay scan time 131.5 minuts. The proposed delay scan time showed statistical reliability applicable to the diagnosis of pancreatic cancer (p<0.05). Delayed scanning with the suggested delay scan time of 131.5 minutes is considered to be useful for the diagnosis of pancreatic cancer compared to general PET / CT scan.hen the delayed test is performed with the proposed delay scan time 131.5 minuts, Compared with general PET/CT scans.

• Journal of Information Technology Applications and Management
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• v.16 no.4
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• pp.205-222
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• 2009

Considering time-lag in the performance evaluation of information system (IS) investment is important because its effect reveals after certain period of time passed. Particularly it is more in the systems of e-government informatization projects which the amount of investment and the scale of business are huge. Many methods to solve this issue have been proposed such as system dynamics methods, simulations, structural equations etc. However, it is still difficult and unsolved problem because collecting practical data for time-lag analysis is very hard. In this paper, we analyze IS time-lag effect through factor analysis using the accumulated practical operational DB data. For the performance evaluation of the G4C system, the representative e-government web portal, we selected eleven factors reflecting time passing in G4C DB data. With these factors this paper conduct time-lag analysis in four view points. First, we conducted 'Stabilizing of G4C system' and got a result that IS is needed about three years for the stabilization. Second, we conducted 'Utilization of G4C system' and got a result that the utilization reaches appropriate level after in three years later after the introduction of G4C system. Third, we conducted 'Cost reduction effect' and got a result that cost reduction is stable in the third year after the introduction of G4C system. Lastly, we conducted 'System maturity effect' and got a result that the system reaches to the quality level that users expect after third to fourth years. According to the results of this research, we found that performance of IS improv continuously not immediately, and it needs three or four years of time-lag.

• Journal of the Korea Concrete Institute
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• v.18 no.4 s.94
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• pp.479-487
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• 2006

This paper deals with a research about the time-dependent behavior analysis for pre-tensioned high-performance concrete(HPC) members. By improving AASHTO-LRFD(2004) method for predicting the creep and shrinkage of normal concrete, and the relaxation of prestressing tendon, a time-dependent behavior analysis of high-performance concrete structures has been introduced. Two methods, the step-function method and the time-step method have been incorporated in the time-dependent analysis. The developed program can predict the initial and time-dependent losses of prestressing forces and the deflections of high-performance concrete structures. The present model has been verified by comparing with the experimental results from the test of time-dependent behaviors of pre-tensioned members using high-performance concrete. From this, the current model gives good relations with the experimental results, but the AASHTO method is not good for the prediction of time-dependent behaviors of high-performance concrete members.

• Journal of Korea Entertainment Industry Association
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• v.14 no.5
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• pp.49-57
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• 2020

This paper analyzed maximized the tension not by functional restriction but by psychological response inducement to form the tension of the horror game from the point of space time view. In order that, We arranged three major situations inducing the tension in the horror game and prepared space time analysis base. Pure fiction time of game itself is applied on game time excluding the time creating the cut-scene and the game space is organized with various combination of three space types. This analysis result can help horror game design by discovering the relationship between space time structure and tension forming of the horror game. These analysis results allow us to find guidelines for the time and space design of horror games that can be flexibly linked to game events and contexts by controlling the player's dynamic/static tension and temporary/continuous tension.

• The Journal of the Korea Contents Association
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• v.11 no.3
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• pp.271-280
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• 2011

Heart Rate Variability (HRV) analysis is a convenient tool to assess Myocardial Ischemia (MI). The analysis methods of HRV can be divided into time domain and frequency domain analysis. This paper uses wavelet transform as frequency domain analysis in contrast to time domain analysis in short term HRV analysis. ST-T and normal episodes are collected from the European ST-T database and the MIT-BIH Normal Sinus Rhythm database, respectively. An episode can be divided into several segments, each of which is formed by 32 successive RR intervals. Eighteen HRV features are extracted from each segment by the time and frequency domain analysis. To diagnose MI, the Neural Network with Weighted Fuzzy Membership functions (NEWFM) is used with the extracted 18 features. The results show that the average accuracy from time and frequency domain features is 75.29% and 80.93%, respectively.

• Convergence Security Journal
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• v.7 no.2
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• pp.49-55
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• 2007

Software failure time presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing. For data analysis of software reliability model, data scale tools of trend analysis are developed. The methods of trend analysis are arithmetic mean test and Laplace trend test. Trend analysis only offer information of outline content. From the subdivision of this analysis, new attemp needs the side of the quality control. In this paper, we discuss process capability analysis using process capability indexs. Because of software failure interval time is pattern of nonnegative value, instead of capability analysis of suppose to normal distribution, capability analysis of process distribution using to Box-Cox transformation is attermpted. The used software failure time data for capability analysis of process is SS3, the result of analysis listed on this chapter 4 and 5. The practical use is presented.

• Journal of the Korean Home Economics Association
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• v.33 no.6
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• pp.73-88
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• 1995

the purpose of this study was to compare the consumption of personal and material resources between working wives and full-time housewives and to conceptualize the cost of working wives by the degree of additional consumption of the resources. The proposed costs of working wives included the long working time (time cost), the short leisure time(energy cost), the increase of expenditures fro services and the serious role conflict(psychological cost). Three methods, t-test, simple regression analysis, multiple regression analysis/tobit analysis were used to analyse the differences in consumption of resources between two groups. On the basis of the analysed results, the employment cost of working wives were discussed.