• 충청수학회지
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• 제17권1호
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• pp.47-56
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• 2004

The nonlinearity of a Boolean function f on $GF(2)^n$ is the minimum hamming distance between f and all affine functions on $GF(2)^n$ and it measures the ability of a cryptographic system using the functions to resist against being expressed as a set of linear equations. Finding out the exact value of the nonlinearity of given Boolean functions is not an easy problem therefore one wants to estimate the nonlinearity using extra information on given functions, or wants to find a lower bound or an upper bound on the nonlinearity. In this paper we extend the notion of auto-correlations of Boolean functions to vector Boolean functions and obtain upper bounds and a lower bound on the nonlinearity of vector Boolean functions in the context of their auto-correlations. Also we can describe avalanche characteristics of vector Boolean functions by examining the extended notion of auto-correlations.

• 한국주거학회논문집
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• 제13권2호
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• pp.79-86
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• 2002

The purpose of this study was to provide guidelines for the remodeling understanding the needs of apartment housing residents. In order to achieve our goal, questionnaire surveys were used. We sampled the questionnaire surveys of the households in Seoul whose apartments had been more than ten years and recently remodeled. The materials collected by a questionnaire survey were analyzed by examining the frequency, percentage on the SPSS/PC+ Statistics package. The results of the questionnaire survey were as follows: (1) Residents tend to demand better environment than an economics benefits from remodeling. (2) Residents wanted to have organized the remodeling group that can help to solve the problems concerning profit and loss among residents. (3) Residents wanted to be supported by government, expand loans from monetary organizations, and have a reserve fund for the remodeling.

• International Journal of Quality Innovation
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• 제9권2호
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• pp.149-160
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• 2008

In a service business, it is difficult to cope with all your customers' needs. They come and go with various wants and when it comes to their own good there are complaining. Such variances in the service business interfere the operation resulting in inefficiency. To come against all those fluctuate wants, Frei is suggesting a new way how to cope with this customer variability in the service business: Low-Cost accommodation and uncompromised reduction. However, his assertion that these solutions can reduce cost and enhance service quality at the same time is empirically not proved. Thus, the following research will be dedicated in the empirical proof whether the solutions mentioned above can enhance service quality while reducing cost by pursuing efficiency in the service business.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.600-603
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• 2004

UAV (Unmanned Aerial Vehicle) is an aerial vehicle that can accomplish the mission without pilot. UAV was developed for a military purpose such as a reconnaissance in an early stage. Nowadays usage of UAV expands into a various field of civil industry such as a drawing a map, broadcasting, observation of environment. These UAV, need vision system to offer accurate information to person who manages on ground and to control the UAV itself. Especially LOS(Line-of-Sight) system wants to precisely control direction of system which wants to tracking object using vision sensor like an CCD camera, so it is very important in vision system. In this paper, we propose a method to recognize object from image which is acquired from camera mounted on gimbals and offer information of displacement between center of monitor and center of object.

• 교통기술과정책
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• 제4권3호
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• pp.105-116
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• 2007

Walking is the first thing an infant wants to do and the last thing an old person wants to give up. Walking is the exercise that does not need a gym. It is the prescription without medicine, the weight control without diet, and the cosmetic that can't be found in a chemist. It is the tranquillizer without a pill, the therapy without a psychoanalyst, and the holiday that does not cost a penny. What's more, it does not pollute, consumers few natural resources and is highly efficient. Walking is convenient, it needs no special equipment, is self-regulating and inherently safe. Walking is as natural as breathing. John Butcher, Founder Walk21, 1999.

• Communications for Statistical Applications and Methods
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• 제17권4호
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• pp.575-589
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• 2010

Exponential L$\acute{e}$evy models have become popular in modeling price processes recently in mathematical finance. Although it is a relatively simple extension of the geometric Brownian motion, it makes the market incomplete so that the option price is not uniquely determined. As a trial to find an appropriate price for an option, we suppose a situation where a hedger wants to initially invest as little as possible, but wants to have the expected squared loss at the end not exceeding a certain constant. For this, we assume that the underlying price process follows a variance-gamma model and it converges to a geometric Brownian motion as its quadratic variation converges to a constant. In the limit, we use the mean-variance approach to find the asymptotic minimum investment with the expected squared loss bounded. Some numerical results are also provided.

• 소음진동
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• 제8권2호
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• pp.283-288
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• 1998

If one wants to control the noise from a duct, then one must have sufficient number of sensors and actuators so that the control system is observable and controllable. A number of sensors and actuators for control of radiating noise from a duct have to be incorporated with the number of modes which one wants to control. These considerations motivated the present study that considers a control system which has less microphones and actuators than required. In this work, by theoretical analysis and numerical simulation, the control performance and robust reliability of such a kind of control system is investigated in terms of sound-field variables and control system variables. Then the possibility of implementation of the robust radiation power control system is verified by theoretical analysis and numerical simulation. In addition, the control performance of the control system is verified by experiment.

• 산업기술연구
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• 제24권B호
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• pp.193-198
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• 2004

We propose and analyse a flexible secure file sharing scheme which can be used for data sharing among members in P2P environment. When a member wants to share data, notification messages are sent to the members with whom the member wants to share data. Each notification message includes one-time password encrypted with the receiver's public key. A member who received the notification message can download the data by using the one-time password. The proposed scheme provides selective sharing, download confirmation and efficient memory management. In terms of security, the proposed scheme supports authentication, entity privacy, replay attack protection and disguise prevention.

• Journal of information and communication convergence engineering
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• 제16권1호
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• pp.48-51
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• 2018

The traditional documents analysis was centered on words based system was implemented using a morpheme analyzer. These traditional systems can classify used words in the document but, cannot help to user's document understanding or analysis. In this problem solved, System needs extract for most valuable paragraphs what can help to user understanding documents. In this paper, we propose system extracts paragraphs of normalized XML document. User insert to system what filename when wants for analyze XML document. Then, system is search for keyword of the document. And system shows results searched keyword. When user choice and inserts keyword for user wants then, extracting for paragraph including keyword. After extracting paragraph, system operating maintenance paragraph sequence and check duplication. If exist duplication then, system deletes paragraph of duplication. And system informs result to user what counting each keyword frequency and weight to user, sorted paragraphs.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.54-59
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• 2014

The rapid tactical operation and mobility are getting important to recently developed the guided weapon systems. And military wants multi-purposes equipment to carry the war more easily. So military wants to have the equipment that can apply without any distinction about environment. For this reason, the robust design is getting more important now to guarantee survivability of equipment. In this paper, we try to check about structural integrity of Fire Control Unit(FCU) which is one of the guided weapon system using dynamic FEM analysis.