• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.65-80
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• 2012

Mobile IP is a simple and scalable global mobility solution. However, it may cause excessive signaling traffic and long signaling delay. So MN (Mobile Node) to the home network in order to reduce the number of location update signaling is necessary to reduce the delay. In this paper, the signaling overhead to be distributed evenly on the boundary of the regional network, each MN's dynamic mobility and traffic load is adjusted according to the PMIPv6 (Proxy Mobile IPv6) networks in the proposed dynamic regional mobility management scheme (dMMS). Each user in a distributed network system that offers the least amount of signaling traffic is tailored to the optimized system configuration. Signaling cost function in order to propose a new discrete analytical model is proposed, MN's mobility and packet arrival patterns. Location update and packet delivery costs to calculate the total average, the optimized area to determine the size of the network is proposed. The results of mathematical analysis, the proposed technique dMMS in terms of reducing the cost of the entire signaling were found to be excellent performance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.5
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• pp.303-311
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• 2003

Since the MPEG-4 visual standard enables content-based functionalities, it is necessary to extract video object from natural video sequences. Segmentation algorithms can largely be classified into automatic segmentation and user-assisted segmentation. In this paper, we propose a user-assisted VOP generation method based on the geometric active contour. Since the geometric active contour, unlike the parametric active contour, employs the level set method to evolve the curve, we can draw the initial curve independent of the shape of the object. In order to generate the edge function from a smoothed image, we propose a vector-valued diffusion process in the LUV color space. We also present a discrete 3-D diffusion model for easy implementation. By combining the curve shrinkage in the vector field space with the curve expansion in the empty vector space, we can make accurate extraction of visual objects from video sequences.

• Explosives and Blasting
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• v.23 no.1
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• pp.47-54
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• 2005

An explosion modeling technique was developed by using the spherical discrete element code, $PFC^{3D}$, which can be used to model the dynamic stress wave propagation phenomenon. The modeling technique is simply based on an idea that the explosion pressure should be applied to a $PFC^{3D}$ particle assembly not in the form of an external force (body force), but in the form of a contact force (surface force). A test blast was conducted for a RC column, whose dimension was $600\times300\times1800$ in millimeters. The initial velocities of the surface movements were measured to be in the range of $14\~18\;m/s$ with the initiation times of $1.5\~2.0m$. Then the blasting procedure was simulated by using the modeling technique. The particle assembly representing the concrete was made of cement mortar and coarse aggregates, whose mirco-properties were obtained from the calibration processes. As a result, the modeling technique developed in this study made it possible for the burden to move with the velocity of $17\~24\;m/s$, which are slightly higher values compared to those of the test blast.

• Korean Journal of Social Welfare
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• v.65 no.3
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• pp.183-206
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• 2013

Using Korean Labor and Income Panel Study (wave 1~11) database, this study analyzed the poverty duration of the poor as a whole and by households' characteristics. For this purpose, I first estimated poverty exit rates and reentry rates applying discrete-time hazard model to the sample, and then calculated poverty duration combining these two probability rates. The results show that about a half of poor households are transitory (short-term) poor with 1~2 years of poverty duration. A quarter is chronic (long-term) poor lasting for 5 or more years of poverty duration. The remained quarter can be categorized as the recurrent or mid-term poor. The socioeconomic characteristics of households greatly affect poverty duration. Long-term poverty is prevalent among female-head households, elderly households, single households, or households headed by a person with a lower level of education. If households' heads do not work, or work as temporary or daily-employed workers, the poverty duration tends to be longer. The findings suggest that the poor consist of various social classes with different characteristics. Efficient anti-poverty policy should be based on thoroughly identifying the specific characteristics and needs of each class.

• The Journal of the Acoustical Society of Korea
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• v.22 no.6
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• pp.434-442
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• 2003

Software internationalization, the process of making software easier to localize for specific languages, has deep implications when applied to speech technology, where the goal of the task lies in the very essence of the particular language. A greatdeal of work and fine-tuning has gone into language processing software based on ASCII or a single language, say English, thus making a port to different languages difficult. The inherent identity of a language manifests itself in its lexicon, where its character set, phoneme set, pronunciation rules are revealed. We propose a decomposition of the lexicon building process, into four discrete and sequential steps. For preprocessing to build a lexical model, we translate from specific language code to unicode. (step 1) Transliterating code points from Unicode. (step 2) Phonetically standardizing rules. (step 3) Implementing grapheme to phoneme rules. (step 4) Implementing phonological processes.

• Journal of KIISE:Databases
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• v.29 no.6
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• pp.441-452
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• 2002

If continuous moving objects are managed by conventional database, it is not possible for them to store all position information changed over time in the database. Therefore, a time period of regular rate is determined and position information of moving objects are discretely stored in the system for every time period. However, if continuous moving objects are managed as discrete model, we will have problems which cannot properly answer to the query about uncertain past or future position information. To solve this problem, in this paper, we propose the method and algorithm which use the history information stored in the same database, to estimate the past or future location of moving objects. The cubic spline interpolation is used to estimate the past location and the mean movement value of the history information is used to predict the future location of moving objects. Finally, from the location estimation experimentation of using virtual trajectory and location sample, we proved that the proposed cubic spline function has less error than the linear function.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2262-2270
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• 1999

In this paper, we describe gesture recognition algorithm using computer vision sensor and HMM. The automatic hand region extraction has been proposed for initializing the tracking of the tele-operation gestures. For this, distance informations(disparity map) as results of stereo matching of initial left and right images are employed to isolate the hand region from a scene. PDOE(positive difference of edges) feature images adapted here have been found to be robust against noise and background brightness. The KNU/KAERI(K/K) gesture instruction set is defined for tele-operation in atomic electric power stations. The composite recognition model constructed by concatenating three gesture instruction models including pre-orders, basic orders, and post-orders has been proposed and identified by discrete HMM. Our experimental results showed that consecutive orders composed of more than two ones are correctly recognized at the rate of above 97%.

• Journal of KSNVE
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• v.10 no.6
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• pp.1067-1074
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• 2000

Numerical methods for calculating both the natural frequencies and buckling loads of columns with the multiple elastic springs are developed. In order to derive the governing equations of such columns, each elastic spring is modeled as a discrete elastic foundation with the finite longitudinal length. By using this model, the differential equations governing both the free vibrations and buckled shapes, respectively, of such columns are derided. These differential equations are solved numerically. The Runge- Kutta method is used to integrate the differential equations, and the determinant search method combined with Regula-Falsi method is used to determine the eingenvalues. namely natural frequencies and buckling loads. In the numerical examples, the clamped-clamped. clamped-hinged, hinged-clamped and hinged-hinged end constraints are considered. Extensive numerical results including the frequency parameters, mode shapes of free vibrations and buckling load parameters are presented in the non-dimensional forms.

• Journal of Internet Computing and Services
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• v.1 no.1
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• pp.47-62
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• 2000

Geographic Information System(GIS) deal with data which can potentially be useful for a wida range of applications. However, the information needs of each application usually vary, specially in resolution, detail level, and representation style, as defined in the modeling phase of the geographic database design. To be able to deal with such diverse needs, the GIS must after features that allow multiple representations for each geographic entity of phenomenon. This paper addresses the problem of formal definition of the objects and their relationships on geographical information systems. The geographical data is divided in two main classes: geo-objects and geo-fields, which describe discrete and continuous representations of spatial reality. I will study the classes and the roles of relationships over geo-fields, geo-objects and nongeo-objects. Therefore, this paper will contribute the efficient design of geographical class hierarchy schema by means of formalizing attribute-domains of classes.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.4
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• pp.482-489
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• 2011

In practical design process, designer needs to find an optimal solution by using full factorial discrete combination, rather than by using optimization algorithm considering continuous design variables. So, ANOVA(Analysis of Variance) based on an orthogonal array, i.e. Taguchi method, has been widely used in most parts of industry area. However, the Taguchi method is limited for the shape optimization by using CAE, because the multi-level and multi-objective optimization can't be carried out simultaneously. In this study, a combined method was proposed taking into account of multi-level computational orthogonal array and TOPSIS(Technique for Order preference by Similarity to Ideal Solution), which is known as a classical method of multiple attribute decision making and enables to solve various decision making or selection problems in an aspect of multi-objective optimization. The proposed method was applied to a case study of the multi-level shape optimization of lower arm used to automobile parts, and the design space was explored via an efficient application of the related CAE tools. The multi-level shape optimization was performed sequentially by applying both of the neural network model generated from seven-level four-factor computational orthogonal array and the TOPSIS. The weight and maximum stress of the lower arm, as the objective functions for the multi-level shape optimization, showed an improvement of 0.07% and 17.89%, respectively. In addition, the number of CAE carried out for the shape optimization was only 55 times in comparison to full factorial method necessary to 2,401 times.