• Journal of Internet Computing and Services
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• v.10 no.5
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• pp.27-32
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• 2009

Colored thread algorithm, suggested to be used for the label switching network, needs to be modified for the packet switching network. In this paper, it is recommended to add a merged state, besides the 3 states - null, colored and transparent - which are resulted from the behaviors of extend, rewind, stall, withdraw and merge events. The original colored thread algorithm is designed to generate a new thread and extend it to the downstream direction with unknown hop count when the thread has revisited the node that was visited. It also suggested rewinding the thread to the downstream direction by the source node, instead of rewinding it upstream direction by the revisited node. If a node received multiple threads which had a same forward equivalent class, then it checks first whether the hop counts are ascending or not. If it is in ascending order, then threads are merged. Otherwise the later thread is stalled until the former thread's color is to be changed to transparent or it is removed. This idea removes the effort of generating a new thread with unknown hop count.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2356-2363
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• 2015

This study deals the optimization design with the simulation based design of a coil spring inserted into the lock nut for preventing the screw thread from loosening at the bolted joint when the high-strength steel bolt with the property class of 10.9 is used and the screw torque of 640 to 800 (Nm) is applied. In this study, structural analysis of assembly composed of bolt, nut and coil spring is carried out to evaluate its safety factors on the basis of the equivalent stress with commercial finite element analysis software. And the design strategy to extract the design improvement from these simulation results is established. An iterative process performed with the proposed design strategy is also proposed for improving the performance of the existing design. At the proposed procedure, the feasible design parameters using response surface method are found, and then these parameters are verified to be optimal or not by comparing with the response values and the simulation results obtained from the feasible parameters.

• Journal of KIISE:Software and Applications
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• v.35 no.2
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• pp.59-69
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• 2008

Automatic obfuscation is known to be the most viable method for preventing reverse engineering intentional1y making code more difficult to understand for security purposes. In this paper, we study and implement an obfuscation method for protecting MS Visual C++ programs against attack on the intellectual property in software like reverse engineering attack. That is, the paper describes the implementation of a code obfuscator, a tool which converts a Visual C++ source program into an equivalent one that is much harder to understand. We have used ANTLR parser generator for handling Visual C++ sources, and implemented some obfuscating transformations such as 'Remove comments', 'Scramble identifiers', 'Split variables', 'Fold array', 'Insert class', 'Extend loop condition', 'Add redundant operands', and 'Insert dead code'. We have also evaluated the performance and effectiveness of the obfuscator in terms of potency, resilience, and cost. When the obfuscated source code has been compared with the original source code, it has enough effectiveness for software protection though it incurs some run-time overheads.

• Journal of the Korea Society of Computer and Information
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• v.22 no.7
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• pp.55-62
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• 2017

Recently, there has been an increasing need for the sharing of microdata containing information regarding an individual entity. As microdata usually contains sensitive information on an individual, releasing it directly for public use may violate existing privacy requirements. Thus, to avoid the privacy problems that occur through the release of microdata for public use, extensive studies have been conducted in the area of privacy-preserving data publishing (PPDP). The k-anonymity algorithm, which is the most popular method, guarantees that, for each record, there are at least k-1 other records included in the released data that have the same values for a set of quasi-identifier attributes. Given an original table, the corresponding k-anonymous table is obtained by generalizing each record in the table into an indistinguishable group, called the equivalent class, by replacing the specific values of the quasi-identifier attributes with more general values. However, query processing over the anonymized data is a very challenging task, due to generalized attribute values. In particular, the problem becomes more challenging with an equi-join query (which is the most common type of query in data analysis tasks) over k-anonymous tables, since with the generalized attribute values, it is hard to determine whether two records can be joinable. Thus, to address this challenge, in this paper, we develop a novel scheme that is able to effectively perform an equi-join between k-anonymous tables. The experiment results show that, through the proposed method, significant gains in accuracy over using a naive scheme can be achieved.

• Land and Housing Review
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• v.2 no.1
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• pp.47-52
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• 2011

Recent advances of technology in materials science have made it easy to respond to user's needs on high performance steel in civil and building structures. The high-performance and high-strength steel are required for large scale structure and high-rise building to have high-strength, high fracture toughness and better weldability etc. Therefore development of 600MPa class steel for mega structure is necessary. high strength steels, however, may have mechanical properties that are significantly different from those of the conventional steels. The application of high-strength steels to building structures should be reviewed as to whether inelastic behavior equivalent to that of conventional steels can be attained or not. This study researched the structural behavior of high strength circular tubes compression and under flexure. Three column tests and three flexural tests were carried out. The suitability of existing design formulae(KBC 2009) and the structural behavior were investigated through these columns and beams with various types.

• Land and Housing Review
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• v.11 no.3
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• pp.11-19
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• 2020

This study aims to examine the relationship between the improvement of the income distribution index from the late 1980s to the 1990s and large-scale housing supply projects such as the 2 million housing construction project. Looking at Korea's economic development in terms of income growth and distribution, GDP has continuously increased since the establishment of the government, especially in the late 1980s. The Gini Index, a representative income inequality index, rapidly deteriorated in the early 1970s, and gradually improved from the late 1980s. The 2 million housing construction project, announced in 1988, supplied a third of the existing nationwide housing stock of 6.5 million units in three years. The project cost was 65 trillion won, equivalent to 50% of Korea's GDP at the time. This study questioned whether the ratio of the number of employed workers in the construction industry was a variable directly affecting the Gini Index. To verify this, the causal relationship between the proportion of employed workers in the construction and manufacturing industries and the Gini Index from 1979 to 2008 was statistically analyzed. For this, the ARIMA model was established for each variable, and the correlation of their residuals was verified. The 2 million housing construction project had the effect of improving income inequality in terms of rising wages for production workers and creating jobs for the low-educated and low-income class. During the project period, the number of middle-income earners increased sharply, and the income gap between the high-income and low-income earners greatly decreased. The expansion of the construction volume can be used as a powerful and direct policy tool for improving income distribution. However, the effect may be limited. When the proportion of workers exceeds the threshold, the effect is weakened.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1842-1850
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• 1997

This paper proposes a new rearrangeable algorithm in multistage reverse shuffle/exchange network. The best known lower bound of stages for rearrangeability in symmetric network is 2logN-1 stages. However, it has never been proved for nonsymmetric networks before. Currently, the best upper bound for the rearrangeability of a shuffle/exchange network in nonsymmetric network is 3logN-3 stages. We describe the rearrangeability of reverse shuffle/exchange multistage interconnection network on every arbitrary permutation with $N{\le}16$. This rearrangeability can be established by setting one more stages in the middle stage of the network to allow the reduced network to be topological equivalent to a class of rearrangeable networks. The results in this paper enable us to establish an upper bound, 2logN stages for rearrangeable reverse shuffle/exchange network with $N{\le}16$, and leads to the possibility of this bound when $N{\le}16$.

• The Korean Journal of Applied Statistics
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• v.29 no.2
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• pp.309-319
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• 2016

For binary classification models, we consider a risk score that is a function of linear scores and estimate the coefficients of the linear scores. There are two estimation methods: one is to obtain MLEs using logistic models and the other is to estimate by maximizing AUC. AUC approach estimates are better than MLEs when using logistic models under a general situation which does not support logistic assumptions. This paper considers imbalanced data that contains a smaller number of observations in the default class than those in the non-default for credit assessment models; consequently, the AUC approach is applied to imbalanced data. Various logit link functions are used as a link function to generate imbalanced data. It is found that predicted coefficients obtained by the AUC approach are equivalent to (or better) than those from logistic models for low default probability - imbalanced data.

• Journal of Mushroom
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• v.16 no.4
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• pp.311-317
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• 2018

The aim of this study was to identify chemical composition and antioxidant activity of phenolic extract of fruiting bodies of an artificially cultivated Hankyong Sanghwang mushroom, Phellinus linteus KACC 93057P (PLHS). The total phenolic content of 60% ethanolic extract of fruiting bodies of two-year-old PLHS grown on Oak wood logs was $19.05{\pm}0.32mg$ gallic acid equivalent (GAE)/g, which was 4-10 times high compared to the other species of mushrooms. 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbisthiazoline-6-sulfonic acid) (ABTS) radical scavenging activities and the ferric reducing antioxidant power (FRAP) value of PLHS were 2-10 and 5 times higher, respectively, than those of the other species of mushrooms. High performance liquid chromatography (HPLC) analysis of ethyl acetate fraction of 70% methanolic extract of the fruiting bodies of PLHS revealed the presence of styrylpyrone-class compounds, davallialactone, hispidin, hypholomine B, and caffeic acid, a compound of the phenylpropanoid pathway.

• Journal of IKEEE
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• v.22 no.4
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• pp.985-991
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• 2018

In this paper, an equivalent circuit reflecting the internal loss of the LLC resonant half bridge converter was proposed and a steady state characteristic equation including the loss factors was derived. Using the results, the frequency characteristics of I/O voltage gain and input impedance were compared with the lossless model In order to verify the proposed model and the derived equation, the main components of the 1kW class LLC resonant half bridge converter were selected under the same conditions and the steady state characteristics such as voltage gain and input impedance were compared. In particular, to compare more closely the steady state error of the two models, we observed the change in switching frequency with respect to the load current, which is considered to be the most important in the actual circuit design stage. As a result, it is confirmed that the error of the operating frequency is significantly improved from the proposed model and the analysis result.