• The KIPS Transactions:PartC
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• v.18C no.2
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• pp.89-96
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• 2011

ASR is an excellent program security technique that protects various data memory areas without run-time overhead. ASR hides the addresses of variables from attackers by reordering variables within a data memory area; however, it can be broken by brute force attacks because of a limited data memory space. In this paper, we propose Multiple ASR to overcome the limitation of previous ASR approaches. Multiple ASR separates a data memory area into original and duplicated areas, and compares variables in each memory area to detect an attack. In original and duplicated data memory areas variables are arranged in the opposite order. This makes it impossible to overwrite the same variables in the different data areas in a single attack. Although programs with Multiple ASR show a relatively high run-time overhead due to duplicated execution, programs with many I/O operations such as web servers, a favorite attack target, show 40~50% overhead. In this paper we develop and test a tool that transforms a program into one with Multiple ASR applied.

• Archives of Plastic Surgery
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• v.35 no.5
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• pp.495-500
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• 2008

Purpose: Adequate tissue oxygenation is considered as an essential factor for wound healing. In the non-diabetic population, an uncompromised macrocirculation generally leads to adequate tissue oxygenation. On the contrary, the macrocirculation in diabetic patients may not correlate with tissue oxygenation because of structural changes in the capillary basement membrane. Nevertheless, many medical professionals in Korea rely on macrocirculation evaluation when predicting wound healing potential of the diabetic ulcers. The purpose of this study is to compare reliability of two common macrocirculation assessment methods, Doppler probing and CT angiography, on tissue oxygenation in diabetic foot patients. Methods: Doppler and CT angiography scores were given according to the patency of the anterior and posterior tibial arteries. Tissue oxygenation was measured by transcutaneous partial oxygen tension($TcpO_2$). Doppler and CT angiography scores were statistically analyzed against $TcpO_2$ values. Sixty-eight diabetic foot ulcer patients were included in this study. Results: The test was carried out on Doppler score and $TcpO_2$ variables displayed a p-value of 0.0202, and concluded that the two variables were statistically dependent. The test used to determine for linear trends between Doppler scores and $TcpO_2$ variables displayed a p-value of 0.0149, displaying statistical linear trend between the two variables. On the contrary, the tests between CT angiography scores and $TcpO_2$ variables showed p-values of 0.1242 and 0.6590, that means no correlation between CT angiography and $TcpO_2$ scores. Conclusion: Doppler probing is more reliable than CT angiography in predicting tissue oxygenation of diabetic foot ulcers.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.175-187
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• 2006

The purpose of this study was to find the relationship between Achilles tendon angle, angular velocity from 2D cinematography utilized to easily analyze the functions of shoes, ankle joint moment, knee joint moment, and hip joint moment from 3D cinematography utilized to predict the injury. Also, this study was to provide the optimal standard to analyze the injury related to the shoes. Subjects in this study were 30 university male students and 18 conditions (2 types of running speed, 3 of midsole hardness, 3 of midsole height) were measured using cinematography and force platform. The results were as following. 1) Hip joint abduction moment was effected by many variables such as running speed, midsole height, maximum achilles tendon angle, ground reaction force. 2) Knee joint rotational moment in running was approximately 1/10 - 1/4 times of the injury critical value and eversion moment was approximately 1/4 - 1/2 times of the injury critical value. 3) Ankle joint pronation moment in running was 1/3 - 1/2 times of the injury critical value. 4) Knee joint rotational moment was found to be irrelevant with maximum achilles tendon angle or angular velocity. 5) Pronation from running was thought to be relevant to rather eversion moment activity than rotational moment activity of knee joint. 6) Plantar flexion abductor of ankle showed significant relationship with the ground reaction force variable. 7) When the loading rate for ground reaction force in passive region increased, extensor tended to be exposed to the injury. Main variables in biomechanical analysis of shoes were impact absorption and pronation. Among these variables, pronation factor was reported to be relevant with knee injury from long duration exercise. Achilles tendon angle factor was utilized frequently to evaluate this. However, as the results of this study showed, the relationship between these variables and injury relating variable of knee moment was so important. Studies without consideration on this finding should be reconsidered and reconfirmed.

• Journal of the Korean Data and Information Science Society
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• v.22 no.5
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• pp.877-884
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• 2011

The decision tree is a representative algorithm of data mining and used in many domains such as retail target marketing, fraud detection, data reduction, variable screening, category merging, etc. This method is most useful in classification problems, and to make predictions for a target group after dividing it into several small groups. When we create a model of decision tree with a large number of input variables, we suffer difficulties in exploration and analysis of the model because of complex trees. And we can often find some association exist between input variables by external variables despite of no intrinsic association. In this paper, we study on the removal method of unnecessary input variables using multiple external association rules. And then we apply the removal method to actual data for its efficiencies.

• The Journal of Korean Association of Computer Education
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• v.18 no.5
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• pp.15-24
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• 2015

The purpose of this study is to analyze variables affecting parents' and elementary school students' value of computer science after creative computer science education, through multiple regression. Many researches on Informatics subject have focused on the effect of the subject contents on students but hardly dealt with parents' recognition. Thereupon, this study pays attention to the value of computer science recognized by parents and analyzes variables substantially affecting value variables of computer science related to parents' support for learning Informatics subjects. This paper did not verify the difference in recognition of parents and students but calculated more concrete influence by conducing multiple regression on the variables affecting the value recognized by each group. This is one of the reasons why this study is meaningful. According to the result of the analysis, variables affecting the value of parents on computer science the most are interest and satisfaction, and in students' case, self-efficacy is the variable affecting the value of computer science the most.

• The Korean Journal of Applied Statistics
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• v.26 no.3
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• pp.441-452
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• 2013

This study analyzed the relationship between key film and a box office record success factors based on movies released in the first quarter of 2013 in Korea. An over-fitting problem can happen if there are too many explanatory variables inserted to regression model; in addition, there is a risk that the estimator is instable when there is multi-collinearity among the explanatory variables. For this reason, optimal variable selection based on high explanatory variables in box-office performance is of importance. Among the numerous ways to select variables, LASSO estimation applied by a generalized linear model has the smallest prediction error that can efficiently and quickly find variables with the highest explanatory power to box-office performance in order.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.117-123
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• 2018

Recently, aqueous method has attracted lots of attention because it enables the solution-processed metal oxide thin film with high electrical properties in low temperature fabrication condition to various flexible devices. Focusing the development of aqueous route, many researchers are only focused on metal oxide materials. However, for expansive application of the aqueous-based metal oxide films, the systematic study of performance change with process variables for the development of aqueous-based metal oxide insulator film is urgently required. Here, we propose importance of process variables to achieve high electrical-performance metal oxide insulator based on the aqueous method. We found that the significant process variables including precursor solution temperature and humidity during the spincoating process strongly affect chemical, physical, and electrical properties of $AlO_x$ insulators. Through the optimization of significant variables in process, an $AlO_x$ insulator with a leakage current value approximately $10^5$ times smaller and a breakdown voltage value approximately 2-3 times greater than un-optimized $AlO_x$ was realized. Finally, by introducing the optimized $AlO_x$ insulators to solutionprocessed $InO_x$ TFTs, we successfully achieved $InO_x/AlO_x$ TFTs with remarkably high average field-effect mobility of ${\sim}52cm^2V^{-1}\;s^{-1}$ and on/off current ratio of 106 at fabrication temperature of $250^{\circ}C$.

• Asia Marketing Journal
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• v.15 no.1
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• pp.155-168
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• 2013

This study describes consumers' movie choices in conjunction with other group members and attempts to reassess the effect of the online word of mouth (WOM) source in a joint decision context. The tendency of many people to go to movies in groups has been mentioned in previous literature but there is no modeling research that studies movie choice from the group decision perspective. We found that ignoring the group movie-going perspective can result in a misunderstanding, especially underestimation of genre preference and the impact of the WOM variables. Most of the studies to measure online WOM effects were done at the aggregate level, and the role of online WOM variables(volume vs valence) is mixed in the literature. We postulate that group-level analysis might offer insight to resolve these mixed understanding of WOM effects in the literature. We implemented the study via a random effect model with group-level heterogeneity. Romance, drama, and action were selected as genre variables; valence and volume were selected as online WOM variables. A choice-based conjoint survey was used for data collection and the models was estimated via Bayesian MCMC method. The empirical results show that (i) both genre and online WOM are important variables when consumers choose movies, especially as group, and (ii) the WOM valence effect are amplified more than the volume effect does as individuals are engaged in group decision. This research contributes to the literature in several ways. First, we investigate movie choice from a group movie-going perspective that is more realistic and consistent with the market behavior. Secondly, the study sheds new light on the WOM effect. At group-level, both valence and volume significantly affect movie choices, which adds to the understanding of the role of online WOM in consumers' movie choice.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.95-98
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• 1996

Universal Learning Network(U.L.N.), which can model and control the large scale complicated systems naturally, consists of nonlinearly operated nodes and multi-branches that may have arbitrary time delays including zero or minus ones. Therefore, U.L.N. can be applied to many kinds of systems which are difficult to be expressed by ordinary first order difference equations with one sampling time delay. It has been already reported that learning algorithm of parameter variables in U.L.N. by forward and backward propagation is useful for modeling, managing and controlling of the large scale complicated systems such as industrial plants, economic, social and life phenomena. But, in the previous learning algorithm of U.L.N., time delays between the nodes were fixed, in other words, criterion function of U.L.N. was improved by adjusting only parameter variables. In this paper, a new learning algorithm is proposed, where not only parameter variables but also time delays between the nodes can be adjusted. Because time delays are integral numbers, adjustment of time delays can be carried out by a kind of random search procedure which executes intensified and diversified search in a single framework.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.423-430
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• 2004

A new active neuro-control strategy for seismic response reduction using modal states is proposed. In order to apply the neuro-control strategy to the given structural system it is needed to select state variables used as inputs into the neural network. If the degrees of freedom of the analytical model is large, there are so many possible combinations of the state variables. And selecting state variables is very complicated and troublesome task for the designer. In order to avoid this problem, the proposed control system adopts modal states as inputs. Since the modal states contain the information of the whole structural system's behavior, it is proper to use modal states as inputs of the neuro-controller. The simulation results show that the proposed the proposed active neuro-control strategy is quite effective to reduce seismic responses. In addition, the consuming time for training proposed neuro-controller is quite shorter than that for the conventional neuro- controller. The results of this investigation, therefore, indicate that the proposed active neuro-control strategy using modal states as the inputs could be effectively used for control seismically excited structures.