• Journal of Korean Institute of Industrial Engineers
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• v.28 no.2
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• pp.128-138
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• 2002

In this paper, we address how to reduce the length of tool retraction in a zigzag pocket machining. Tool retraction, in a zigzag pocket machining, is a non-cutting operation in which the tool moves to any remaining regions for machining. We developed an algorithm of generating tool retraction length in convex or concave polygonal shapes including islands. In the algorithm, we consider concave areas of cutting direction in the polygonal shape. Considering concave areas of cutting direction, the polygonal shape is decomposed to subregions which do not need any tool retraction. Using the proposed algorithm, we calculated the shortest length of tool retraction in cutting direction. Examples are shown to verify the validity of the algorithm.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1157-1159
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• 1987

A syntactic and semantic approach is used to make type classification based on feature points(whorl, delta, core) and the shape of flow line around feature points. The image is divided into 30 by 30 subregions which are represented in the average direction and 4-tuple direction component. Next the relaxation process with singularity detection and convergency checking is performed. A set of semantic languages is used to describe the major flow line around the extracted feature points. LR(1) parser and feature transfer function are used to recognize the coded flow patterns. The 72 fingerprint impressions is used to test the proposed approach and the rate of the classification is about 93 percentages.

• Journal of Korean Society of Rural Planning
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• v.1 no.2
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• pp.33-42
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• 1995

For formulation of the rational land us2 plan in regional base, it is a basic and prior condition to categorize total planning area into some functional subregions by purposely-selected indicators. As one of quantitive approaches to the areal categorization in rural area, Principal Component Analysis(PCA) was introduced and testified its applicability through a case study on Sunheungdistrict(called as myun in Korea) area, Youngpoong-county, Kyungbuk-province, Korea. Areal analysis by PCA was carried out on rurality and urbanity of parish-level area(ri in Korea) respectively. By use of PCA analysis results, classifying matrix was made through categorization of both index scores. Among 18 ri's of the case study area, 12 was classified as rural-dominated areas, 2 as urban- dominated areas, and reamaining 3 as intermediate areas.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.2
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• pp.153-162
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• 2014

A novel robust $H_{\infty}$ switching tracking control design method with disturbance observer is proposed for the near space interceptor (NSI) with aerodynamic fins and reaction jets. Initially, the flight envelop of the NSI is divided into small subregions, and a slow-fast loop polytopic linear parameter varying (LPV) model is proposed, to approximate the nonlinear dynamic of the NSI, based on the Jacobian linearization and Tensor-Product (T-P) model transformation approach. A disturbance observer is then constructed, to estimate the modeled disturbance. Subsequently, based on the descriptor system method, a robust switching controller is developed, to ensure that the closed-loop descriptor system is stable with a desired $H_{\infty}$ disturbance attenuation level. Furthermore, the outcome of the proposed switching tracking control problem is formulated as a set of linear matrix inequalities (LMIs). Finally, simulation results demonstrate the effectiveness of the proposed design method.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.1-5
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• 2008

Primary brain tumor accounts for 1.4% of entire cancer. For males between the ages of 15 and 34 years, central nervous system tumors account for the leading cause of cancer death. $^{18}F-FDG$ PET has been reported that it can provide important diagnostic information relating to tumor grading and differentiation from non- tumorous condition. In addition, the degree of FDG metabolism carries prognostic significance. By mapping the metabolic pattern of heterogeneous tumors, $^{18}F-FDG$ PET can aid in targeting for stereotactic biopsy by selecting the subregions within the tumor that are most hypermetabolic and potentially have the highest grade. According to clinical research data, FOG PET is expected to be a helpful diagnostic tool in the management of brain tumors.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.101-103
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• 1999

This paper presents an analysis of 2-dimensional(2-D) multi-regions problem using boundary integral equation method(BIEM). When compared with finite element method(FEM), there are only a few unknown variables in BIEM because it implements numerical analysis only for the surface or boundary of a model. As a result, a lot of computational memory and time can be saved. Procedure to analyze 2-D multi-regions problem using potentials and its derivatives in a boundary as unknown variables, first, numerical analysis is performed for each of subregions. And then interface continuity condition is applied to the interface between them and Gauss Quadrature Formula are adopted to solve singular integral in a boundary in this paper.

• Atmosphere
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• v.18 no.4
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• pp.493-506
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• 2008

In order to examine the variational features of Asian dust outbreak in recent years, observed WMO synop data were employed for the period from 1996 to 2007. We first divided Asian dust source regions into four subregions; 1) Taklamakan, 2) Gobi, 3) Inner Mongolia-Manchuria and 4) Loess, and the meteorogical variables such as wind speed, precipitation and threshold wind speed observed during the Asian dust outbreak period were compared with those during non-Asian dust period. The results showed that temporal variation of occurrence frequency of dust outbreak had a strong positive correlation with the frequency of strong wind speed and low precipitation in each of the 4 source regions. Spatial distributions of frequency of dust occurrence after 2002 showed increasing trend in Gobi and Inner Mongolia-Manchuria but decreasing trend in Loess region. This is showing a shift in main source region toward Northwest, especially since 2003.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.73-75
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• 1999

The time harmonics of an inverter output voltage cause high frequency currents in the rotor bars of a squirrel cage induction motor, so that the harmonic copper loss density increases in the upper lesion of the bars. Such an higher loss density makes an nonuniform thermal source and deforms the bars due to the thermal stress. Therefore, in this paper, the copper loss distribution in the rotor bar of an inverter-fed induction motor, which is the source of the thermal stress, is analyzed by the time-stepping finite element method. As a result, the harmonic copper losses of 11 subregions in a bar are calculated and compared with those of sinusoidally fed induction motor.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.299-300
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• 2007

Along with the development of imaging sensors, hyperspectral imaging technology is growing rapidly and contributing to many fields of science nowadays. However, the bulky size and complex structure make it difficult to be processed. Focused on in this paper is the clustering utility, implemented in HYVEW, a program involving tools and functions to manipulate with hyperspectral images. The clustering process aims to partition the surface of the imaged area into subregions by grouping the spectra subject to the similarity of spectra.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.91-99
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• 2004

An unstructured tetrahedral mesh generation algorithm has been presented. In order to construct better meshes in interior region by using an advancing front technique, a connecting operator and a local finishing operator II have been developed in addition to the existing operators. Before applying digging operators that generate new nodes inside of a meshing region, a connecting operator is employed that uses existing nodes which satisfy certain conditions for producing well-conditioned elements. The local finishing operator II is introduced to terminate the meshing process more flexibly on remaining subregions. With these new operators, tetrahedral meshing process becomes more robust and good quality of meshes are constructed.