• International Journal of Fluid Machinery and Systems
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• v.10 no.3
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• pp.240-253
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• 2017

Latin hypercube sampling is widely used design-of-experiment technique to select design points for simulation which are then used to construct a surrogate model. The exploration/exploitation properties of surrogate models depend on the size and distribution of design points in the chosen design space. The present study aimed at evaluating the performance characteristics of various surrogate models depending on the Latin hypercube sampling (LHS) procedure (sample size and spatial distribution) for a diverse set of optimization problems. The analysis was carried out for two types of problems: (1) thermal-fluid design problems (optimizations of convergent-divergent micromixer coupled with pulsatile flow and boot-shaped ribs), and (2) analytical test functions (six-hump camel back, Branin-Hoo, Hartman 3, and Hartman 6 functions). The three surrogate models, namely, response surface approximation, Kriging, and radial basis neural networks were tested. The important findings are illustrated using Box-plots. The surrogate models were analyzed in terms of global exploration (accuracy over the domain space) and local exploitation (ease of finding the global optimum point). Radial basis neural networks showed the best overall performance in global exploration characteristics as well as tendency to find the approximate optimal solution for the majority of tested problems. To build a surrogate model, it is recommended to use an initial sample size equal to 15 times the number of design variables. The study will provide useful guidelines on the effect of initial sample size and distribution on surrogate construction and subsequent optimization using LHS sampling plan.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.173-178
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• 2022

With the development of information technology, the popularization of 5G and cloud computing has accelerated the circulation and digital transformation of information. In the network information society where information is rapidly increasing, it is very important to have the ability to manage and collect the required information. In particular, the information storage and management functions of cloud services are widely used among young people. This research takes the social factors of accepting cloud services as the breakthrough point, and takes young consumers aged 20-30 as the survey object, and designs a research model according to the development of cloud computing technology. The findings verify the influence of social factors on cloud service acceptance and 20-30-year-old consumers' intention to use cloud services. The partial and complete mediating effects of perceived ease of use were verified from the influence relationship between social factors and exploitation intention. Finally, this study provides inspiration for the development direction of cloud computing technology through empirical analysis.

• Journal of Korean Philosophical Society
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• no.122
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• pp.85-134
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• 2018

In this article, I will provide a philosophical discourse on digital sexual violence that is a technological version of male violence. First, critical analysis of the mechanism of the spatiality and the temporality of the hidden and illicit camera is developed to focus on the immeasurable damage of this violence. I elaborate a notional division between digital sexual violence and cyber sexual violence. Secondly, the ease of taking images of women's bodies and the rapid transmission of these images through the advancement of digital communication technology and hyperconnectivity, lead to use these images as a new digital monet for men. They consolidate their male solidarity by reaffirming female inferiority and humiliating women. Thirdly, the invention of the structure of the new affect to resist to digital sexual violence is crucial. For that, it would be necessary to pass from the sexual shame to the sexual displeasure and to the socio-political indignation. These would create another opportunity to resist to digital sexual violence.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.281-293
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• 2023

Industrial control systems (ICS) are increasingly targeted by security incidents as attackers' knowledge of ICS characteristics grows and their connectivity to information technology expands. Vulnerabilities related to ICS are growing rapidly, but patching all vulnerabilities in a timely manner is challenging. The common vulnerability assessment system used to patch vulnerabilities has limitations as it does not consider weaponization after discovery. To address this, this study defines criteria for classifying attacker skill levels based on open information including operating technology and vulnerability information in ICS. The study also proposes a method to evaluate vulnerability severity that reflects actual risk and urgency by incorporating the corresponding attribute in the existing severity score calculation. Case studies based on actual accidents involving vulnerabilities were conducted to confirm the effectiveness of the evaluation method in the ICS environment.

• Journal of Food Hygiene and Safety
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• v.30 no.3
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• pp.217-226
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• 2015

This study was conducted to establish a standardized process for developing food safety health indicators. With this aim, we proposed a standardized process, accessed the validity of the suggested process by performing simulations, and provided a method to utilize the indicators. Developing process for domestic environmental health indicators was benchmarked to propose a standardized process for developing food safety health indicators, and DPSEEA framework was applied to the development of indicators. The suggested standardized process consists of an exploitation stage and a management stage. In the exploitation stage, a total of 6 procedures (initial indicators suggestion, candidate indicators selection, data availability assessment, feasibility assessment, pilot study, and final indicator selection) are conducted, and the indicators are routinely calculated and officially announced in the management stage. The exploitation stage is operated by an interaction between a task force team who manages the overall process, and an advisory committee (minimum of 4 in academia, 2 in research, 4 in specialists of Ministry of Food and Drug Safety) who reviews and performs evaluations on the indicators. The standardized process was simulated with 45 initial indicators, and total of 4 indicators (17 detailed indicators) were selected: 'Proportion of domestic fruit/vegetable receiving 'acceptable' in the evaluation of pesticide/herbicide residues', 'Food-borne disease outbreaks', 'Food-borne legal infectious disease incidence', 'Salmonellosis incidence'. Synthetic food safety health index was derived by calculating percent difference with the data from 2010 to 2012. Results showed that when comparing the year 2010 to 2011, and 2011 to 2012, the overall food safety status improved by 10.37% and 9.87%, respectively. In addition, the contribution of indicators to the overall food safety status can be determined by looking into the individual indicators, and the synthetic index may be illustrated to enhance the ease of interpretation to the public and policy makers. In overall, food health safety indicators can be useful in many ways and therefore, attention should be drawn to conduct further studies and establish related legislations.