• Journal of the Korean Society of Safety
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• v.21 no.3 s.75
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• pp.94-100
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• 2006

The goal of this study is to show the way to increase the safety of deteriorated PSC beam bridges by the to-box reinforcing method. This method is to change the open girder section into the closed box section by connecting bottom flanges of neighboring PSC girders with the precast panels embedding PS tendons at the anchor block. The box section is composed of three concrete members with different casting ages, RC slab, PSC beam, precast panel. This different aging requires a time-dependent analysis considering construction sequences. Reliability index and failure probability are produced by the AFOSM reliability analysis. Transversely five schemes and longitudinally two schemes are considered. The full reinforcing scheme, transversely and longitudinally, shows the highest reliability index, but it requires more cost for retrofit. The partial reinforcing scheme 4, 4-1 are recommended in this study as the economically best scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.1
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• pp.101-114
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• 1991

In a DES-like cryptosystem, the S(ubstitution) boxes determine its cryptographic strength as well as its nonlinearity. When in an S box a part of the output depends on a part of the input. It can be broken by the chosen plaintext attack. To prevent this attack, every output bit should changes with a probability of one half when ever a single input bit is complemented. We call this criterion Strict Avalanche criterion(SAC), which was proposed by Webster and Tavared. In this paper, we propose simple construction method of Boolean functions satisfying the SAC and bijective functions satisfying the maximum order SAC in order to design cryptographically desirable S-boxes. Also, practical construction examples of S-boxes are provided.

• Journal of Korea Game Society
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• v.20 no.2
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• pp.123-138
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• 2020

The purpose of this study is to examine the probabilities and expenditures of game users' loot box purchases and to verify if there are differential effects on adults and teenagers. Results show that the purchasing probability of teenagers was significantly lower than that of adults, and the amount was also low or not significant. In addition, loot box purchasing has a positive correlation with the total expenditure on games, but teenage buyers have a lower game spending than adults do. This suggests the possibility that loot boxes are considered as cost-saving products for teenage gamers.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.330-337
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• 2002

The objective of the earthquake resistant design of structures is to satisfy on the one side the minimization of damage requirement under earthquakes with high probability of occurrence during the design life and on the other side the no collapse requirement under the design seismic event with low probability of occurrence. The two requirements are satisfied with the minimum strength of substructure as well as the ductile failure mechanism presented in the codes. In this study seismic performance is evaluated with two bridges which have steel box superstructures and T type, II type piers as substructures. In order to satisfy the two requirements redesign of both substructures and steel bearings are carried out.

• Wind and Structures
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• v.26 no.4
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• pp.231-251
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• 2018

The objective of the investigation is the analysis of wind-tunnel experimental errors, associated with the measurement of aeroelastic coefficients of bridge decks (Scanlan flutter derivatives). A two-degree-of-freedom experimental apparatus is used for the measurement of flutter derivatives. A section model of a closed-box bridge deck is considered in this investigation. Identification is based on free-vibration aeroelastic tests and the Iterative Least Squares method. Experimental error investigation is carried out by repeating the measurements and acquisitions thirty times for each wind tunnel speed and configuration of the model. This operational procedure is proposed for analyzing the experimental variability of flutter derivatives. Several statistical quantities are examined; these quantities include the standard deviation and the empirical probability density function of the flutter derivatives at each wind speed. Moreover, the critical flutter speed of the setup is evaluated according to standard flutter theory by accounting for experimental variability. Since the probability distribution of flutter derivatives and critical flutter speed does not seem to obey a standard theoretical model, polynomial chaos expansion is proposed and used to represent the experimental variability.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1998.12a
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• pp.335-343
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• 1998

In Asiacrypt'96, Nyberg obtained an upper bound of the maximum average of differential probability for a generalized Feistel network. In this paper, we prove a counterexample to Nyberg's result is given.

• Journal of the Society of Disaster Information
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• v.15 no.4
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• pp.626-633
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• 2019

Purpose: The primery objecting of this paper is to explore the seismics fragility of curved bridge based on the change of girder section. Method: The cross section of the bridge structure was constructed with I, T, and Box shapes and then, in order to perform the seismic fragility 24 seismic ground motions were used, including Gyeongju Pohang Earthquake. Result: Fist, T-Shape of the bridge strucrue was much fragility in terms of the stress on girder section, in comparison to the other shapes. The seismic fragilies of the structures with respect to displacement(drift ratio), however, were shown simialr. Conclusion: In other to wvaluation the seismic fragility of curved structure using different girder shapes, analytical models of the structure were constructed and then, the probability failure of box-shape girder was shown lower probability. In further, Parametric studies of curved structures must be conducted.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.549-555
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• 2023

Jacking force loss management inside the PSC Box girder of a common high-speed railway is a very important feature in girder performance, and requires detailed management during the maintenance of the girder. This study aimed to analyze the timing of re-tension prediction of PSC Box girder based on the reduction level of the packing force inside the girder and the results of the tension loss measured without the train load test. As a result of predicting the timing of re-tension according to the level of tension reduction of the PSC Box Girder, the Jacking Force Loss curve was gently analyzed before the structure reached 17 years after confirmed completion, and 17 years later, it was found that the jacking force loss curve progressed rapidly. The results confirmed that the tension of the structure decreases with the service life increase, but considerably decreases as the structure ages. Therefore, more data and research on tension loss of facilities over 20 years are much required.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.4
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• pp.139-144
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• 1999

Based on the recent developments of the reliability-based structural analysis and design as well as the extending knowledge on the probabiliistic characteristics of load and resistances, the probability based design criteria have been successfully developed for many standards. Since the probabilistic characteristics depend highly on the local load and resistances, it is recognized to develop the design criterion compatible with domestic requirements. The existing optimum design methods, which are generally based on the structural theory and certain engineering experience, do not realistically consider the uncertainties of load and resistances and the basic reliability concepts. This study is directed to propose a optimum design based Expected Total Cost Minimization on P.S.C Box Girder Bridge system which could possibly replace optimum design based traditional provisions of the current code, based on the Neldel-Mead Method reliability theory.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.276-285
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• 2008

These days the automobile industry, which has rapidly progressed, has been an indispensable part in social and economic activities as well as its research and development have been activated in response to various needs of consumers and markets. The second and third generation control system, getting count on safety and convenience differently than early circuits, cause the hypertrophy of wire harness. The J/Box(Junction Box), which distributes power and wires, was developed to solve the problem. As vehicles have been better in quantity and intelligence, however, environment-friendly electric apparatus system has continuously increased and ITS(Intelligent Transport System) has been introduced in earnest. In result, wires got complicated and multilateral and also there has been a stronger probability that vehicles are out of order due to various problems including mechanical failure. In this study, ISJB(Intelligent Smart Junction Box) was introduced to solve the problem. The diagnosis system was applied to prevent the overload and short of ISJE. Also, the state of vehicles displayed so that drivers monitor it in motion. Likewise error data are saved in the memory so that such data can be analyzed retrospectively. The busbar was adopted in to the main power terminal and the part of power pattern was coverd by lead. Because ISJB is more sensitive to heat in comparison to the busbar type J/Box. With regard the circuits related with safe, alternative circuits were set up in order that electronic devices may be normally operated even when an error arises. ISJB is expected to improve the safety and quality of vehicles.