• Journal of the Korean Society of Systems Engineering
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• v.20 no.1
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• pp.76-84
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• 2024

This study investigates the design of an optical observation system for continuously tracking unknown space object targets within the telescope's field of view at a short cycle rate of several to tens of frames per second. Through modeling and integrated simulation by design variables, we aim to identify combinations that satisfy the performance effectiveness scale. The study demonstrates the effectiveness of a model-based simulation analysis approach in rapidly identifying design parameters that meet specific performance requirements. By leveraging numerical models tailored to the desired performance analysis level, the approach provides a robust foundation for decision-making, eliminating reliance on empirical methods or vague estimations.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.6
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• pp.773-785
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• 2014

For decades, modeling of pilots has been intensively studied due to its advantages in reducing costs for training and enhancing safety of pilots. In particular, research for modeling of pilots' non-kinetic behaviors which refer to the decisions made by pilots is beneficial as the expertise of pilots can be inherent in the models. With the recent growth in the amount of combat logs accumulated, employing statistical learning methods for the modeling becomes possible. However, the combat logs consist of heterogeneous data that are not only continuous or discrete but also sequence independent or dependent, making it difficult to directly applying the learning methods without modifications. Therefore, in this paper, we present a kernel function named hybrid sequence kernel which addresses the problem by using multiple kernel learning methods. Based on the empirical experiments by using combat logs obtained from a simulator, the proposed kernel showed satisfactory results.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.370-379
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• 2015

Handling constantly evolving configurations of aircraft can be inefficient and frustrating to design engineers, especially true in the early design phase when many design parameters are changeable throughout trade-off studies. In this paper, a physics-based design framework using parametric modeling is introduced, which is designated as DIAMOND/AIRCRAFT and developed for structural design of transport aircraft in the conceptual and preliminary design phase. DIAMOND/AIRCRAFT can relieve the burden of labor-intensive and time-consuming configuration changes with powerful parametric modeling techniques that can manipulate ever-changing geometric parameters for external layout of design alternatives. Furthermore, the design framework is capable of generating FE model in an automated fashion based on the internal structural layout, basically a set of design parameters describing the structural members in terms of their physical properties such as location, spacing and quantities. The design framework performs structural sizing using the FE model including both primary and secondary structural levels. This physics-based approach improves the accuracy of weight estimation significantly as compared with empirical methods. In this study, combining a physics-based model with parameter modeling techniques delivers a high-fidelity design framework, remarkably expediting otherwise slow and tedious design process of the early design phase.

• Textile Coloration and Finishing
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• v.18 no.4
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• pp.43-48
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• 2006

A phthalocyanine reactive dye was applied to nylon fibers to study the effects of the temperature and pH on % exhaustion and fixation. In addition, appropriate predictable empirical models, relatively new approaches in dyeing process, were developed incorporating interactions effects of temperature and pH for predicting the both % exhaustion and fixation. The significance of the mathematical model developed was ascertained using Excel regression (solver) analysis module. A very high correlation coefficient was obtained ($R^2=0.9895$ for % exhaustion, $R^2=0.9932$ for fixation) for the model which shows prominent prediction capacity of the model for the unknown conditions. The predictable polynomial equations developed from the Experimental results were thoroughly analyzed by ANOVA (Analysis of Variance) statistical concepts.

• Textile Coloration and Finishing
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• v.19 no.2
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• pp.14-23
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• 2007

This research article explores the use of phthalocyanine reactive dye on nylon substrate. The effect of factors such as pH, temperature, liquor ratio and alkali addition on level of dye exhaustion, fixation and total fixation efficiency. Low pH, high temperature and low liquor ratio were found to be suitable conditions for maximum % exhaustion values. The effect of sulphatoethylsulphone(SES) and vinylsulphone(VS) form of the dyes on level of dye fixation was also discussed. The optimized exhaustion (%E), fixation(%F) and total fixation efficiency were determined. Modification of the dyeing process with alkali addition displayed that dye fixation(%) increased by alkali addition. Vinylsulphone(VS) moiety of the dye was found to be superior to. maximum fixation (%F). Appropriate predictable empirical models, relatively a new approach in dyeing processes, were developed incorporating interactions effects of temperature, pH and liquor ratio for predicting % exhaustion, fixation and total fixation efficiency. The significance of the mathematical model developed was ascertained using microsoft excel regression(solver) analysis module. High correlation coefficient was obtained (R2=0.9895 for % exhaustion, R2=0.9932 for fixation, R2=0.9965 for total fixation efficiency) for the model which shows prominent prediction capacity of the model for my conditions. The predictable polynomial equations developed from tile experimental results were thoroughly analyzed by ANOVA (Analysis of Variance) statistical concepts.

• Journal of the Korean Institute of Gas
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• v.24 no.2
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• pp.50-55
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• 2020

The heuristics accumulated in the field activities of firefighters were reviewed through big data analysis of fire occurrences in Gyeonggi-do and researched to be utilized for proper fire prevention activities according to time, day, and target through quantitative modeling. Empirical rules with high sympathy were collected through direct interviews with firefighters. Among them, the rule of thumb that "Friday is the most fire-prone" is considered to be the most important in terms of fire monitoring and prediction. A big data comparison analysis was conducted, including the number of fires and damages that occurred in Gyeonggi-do in 2018. Furthermore, fire occurrence patterns by region, day of the week, time of day, and building type were derived. Regarding empirical rules that have been validated through research, relatively inexperienced firefighters also can make decisions by relying on refined quantitative predictive modeling and empirical rules including local government and time-based factors that reflect big fire occurrence data.

• The Transactions of the Korea Information Processing Society
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• v.5 no.11
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• pp.2954-2972
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• 1998

It is expected that the transport of compressed video will become a significant part of total network traffic because of the widespread introduction of multimedial services such as VOD(video on demand). Accordingly, VBR(variable bit-rate) encoded video will be widely used, due to its advantages in statistical multiplexing gain and consistent vido quality. Since the transport of video traffic requires larger bandwidth than that of voice and data, the characterization of video source and traffic modeling is very important for the design of proper resource allocation scheme in ATM networks. Suitable statistical source models are also required to analyze performance metrics such as packet loss, delay and jitter. In this paper, we analyzed and described on the characterization and traffic modeling of MPEG video sources. The models are broadly classified into two categories; i.e., statistical models and deterministic models. In statistical models, the models are categorized into five groups: AR(autoregressive), Markov, composite Marko and AR, TES, and selfsimilar models. In deterministic models, the models are categorized into $({\sigma},\;{\rho}$, parameterized model, D-BIND, and Empirical Envelopes models. Each model was analyzed for its characteristics along with corresponding advantages and shortcomings, and we made comparisons on the complexity of each model.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.1
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• pp.131-147
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• 2016

This study investigated the relationship between fashion behavior, impression management behavior, and career success. A conceptual model and hypotheses were established based on theoretical linkages between the constructs. Thereafter, empirical data were collected using a set of questionnaires. For this reason, the sample was taken from 720 office workers' who worked at 14's Korea Enterprise, 697 of which was used for an empirical analysis (sample: men over 30 years of age and more than three years continuous service). This study conducted an exploratory factor analysis and confirmatory factor analysis for the validity test. Cronbach's alpha test is used for the reliability test. Moreover, PLS structural equation modeling (SEM) was employed to test hypothesized relationships in the conceptual model (SPSS 20.0 window/Smart PLS 3.0). This study shows that the proposed model is reasonably fit to the actual data. The following results were obtained from the analyses. First, fashion behavior and impression management behavior is positively related to career success. The result shows that economics of the fashion behaviors sub-types were statistically more significant to influence career success. The self-focused of the impression management behavior sub-types were more than statistically significant to influence career success. This finding has great implications to understand self-management behavior and the career success of male office workers.

• Geomechanics and Engineering
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• v.18 no.4
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• pp.339-352
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• 2019

Rockmass parameters are used in the design of engineering structures built in rock and soil. One of the most important of these parameters is the rockmass Emass (Emass). Determination of the Emass of rockmass is a long, hard and expensive job. Therefore, empirical formulas developed by different researchers are used. These formulas use the elastic modulus of the material as a parameter. This value is a constant value in the design. However, engineering structures remain under different loads depending on many factors, such as topography, geometry of the structure, rock / soil properties. Time is other important parameter for rock/soil structure. With the start of the excavation, the loads that the structure is exposed to will change and remain constant at one level. In the new proposed method, the use of different Emass calculated from empirical formulas using the different material elastic modulus, which has different values under different loads as time dependent, was investigated in rock/soil structures during design. The performance of the stability analysis using different deformation modules was questioned by numerical modeling method. For this query, a sub-routine which can be integrated into the numerical modeling software has been developed. The integrated sub-routine contains the formula for the Emass, which is calculated from the material elasticity modules under time dependent and different constant loads in the laboratory. As a result of investigations conducted in 12 different field studies, the new proposed method is very sensitive.

• Korean Journal of Labor Studies
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• v.19 no.1
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• pp.65-104
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• 2013

This study aims to examine the intermediary roles of employee performance between high performance work system (HPWS) and its operational performance on the resource based view. Taking into account the unit of analysis, this study used a hierarchical linear modeling analysis in order to test rigorously the association between HPWS at the organisational level and employee performance at the individual level. For this empirical test, Human Capital Corporate Panel (HCCP) data including 316 firms and 7,872 respondents (including 923 team leaders) were used. To meet the unit of analysis and test the mediation effect, data at the individual and team level were aggregated into the organisational level. The empirical results show that HPWS have a positive impact on operational performance as well as employee performance such as job satisfaction, organisational commitment and organisational trust. Regarding the mediation effect, job satisfaction and organisational trust mediate between HPWS and operational performance. Theoretical implications are discussed in conclusion.