• Journal of the Korean Mathematical Society
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• v.47 no.5
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• pp.1031-1054
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• 2010

Let $\mathbb{Z}^n$ be the Cartesian product of the set of integers $\mathbb{Z}$ and let ($\mathbb{Z}$, T) and ($\mathbb{Z}^n$, $T^n$) be the Khalimsky line topology on $\mathbb{Z}$ and the Khalimsky product topology on $\mathbb{Z}^n$, respectively. Then for a set $X\;{\subset}\;\mathbb{Z}^n$, consider the subspace (X, $T^n_X$) induced from ($\mathbb{Z}^n$, $T^n$). Considering a k-adjacency on (X, $T^n_X$), we call it a (computer topological) space with k-adjacency and use the notation (X, k, $T^n_X$) := $X_{n,k}$. In this paper we introduce the notions of KD-($k_0$, $k_1$)-homotopy equivalence and KD-k-deformation retract and investigate a classification of (computer topological) spaces $X_{n,k}$ in terms of a KD-($k_0$, $k_1$)-homotopy equivalence.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.11
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• pp.1052-1057
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• 2007

A highly reliable Video Transmission System (VTS) was developed in order to obtain both video and digital data simultaneously in the real time flight test situation of a flying vehicle. The VTS integrates GPS data, digital telemetry data and video signals into a compact digital data package which is compressed and processed by an MPEG-2 Encoder and a DVB-S modulator respectively. The DVB-S modulator is composed of a specially devised Forward Error Correction processor and base band QPSK modulator. The designed VTS was verified and proved for its required functioning and performance through separate flight tests using an airplane and missiles.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.1
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• pp.63-74
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• 2011

LED design works make user experience the conditions of time and space, and enable maximized spatial exploration and pursuit of ultimate sources. Light itself includes an ample dimension of time and, through the process of on and off, time-duration, similarity, and discontinuation is reorganized. LED design works make people experience the conditions of time and space, and enable maximized spatial exploration and pursuit of ultimate sources. LED design have been approached more from the viewpoint of material than from the viewpoint of aesthetics. LED based environmental design will be embedded deeply into our life with the technology of ubiquitous city. As the problem of the light intensity, tempo of change LED motion graphic and colors, substitutability is almost completely resolved now, LED is have more potentials than any other material as a tool of motion graphic. These result well make that using of LED is could be better useful from now on. In edition, users could be offered better beneficial lighting environment, and they will enjoy their better lives in the future.

• Korean Journal of Digital Imaging in Medicine
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• v.12 no.2
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• pp.97-101
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• 2010

This experimental study is carried out one of the General Hospital in Kyungbok providence. Abdomen Phantom being located Anterior-posterior(AP) position on portable bed, and the portable X-ray generating device was placed the phantom at $-90^{\circ}$ direction. The experiment were set 65 kVp, 10 mAs, $10{\times}10\;cm^2$, 100 cm(FOD) for the measurement. Digital proportional counting tube survey meter was used for measuring the space scatter dose. Measurement points of horizontal distribution was set up at $30^{\circ}$ interval by increasing 50 cm radius of upside, downside, left and right. Vertical distribution of measurement points were set up for the vertical plane with a radius of at $30^{\circ}$ intervals with 50cm increments. It is concluded that longer distance from the soure of X-ray significantly decrease radiation dose to the patient and use of the radiation protection device should be applied in clinical practice to reduce dose to the patient.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.10
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• pp.896-901
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• 2015

The skin-frame type structure is designed to investigate the thermal deformation of the wing skin induced by the temperature gradient. In order to effectively simulate the temperature gradient on the wing specimen, a water cooling system is devised on the frame of the specimen. Out of surface skin deformation of the skin-frame type structure made of SUS304 material with respect to the temperature is successfully measured using the digital image correlation (DIC) technique including quantitative evaluation of the measurement uncertainty.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1442-1462
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• 2014

Packet classification is a key technology of the Internet for routers to classify the arriving packets into different flows according to the predefined rulesets. Previous packet classification algorithms have mainly focused on search speed and memory usage, while overlooking update performance. In this paper, we propose PreCuts, which can drastically improve the update speed. According to the characteristics of IP field, we implement three heuristics to build a 3-layer decision tree. In the first layer, we group the rules with the same highest byte of source and destination IP addresses. For the second layer, we cluster the rules which share the same IP prefix length. Finally, we use the heuristic of information entropy-based bit partition to choose some specific bits of IP prefix to split the ruleset into subsets. The heuristics of PreCuts will not introduce rule duplication and incremental update will not reduce the time and space performance. Using ClassBench, it is shown that compared with BRPS and EffiCuts, the proposed algorithm not only improves the time and space performance, but also greatly increases the update speed.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.4
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• pp.69-79
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• 2015

This research proposes a modified data hiding method to hide data in a slack space of an NTFS index record. The existing data hiding method is for anti-forensics, which uses traces of file names of an index entry in an index record when files are deleted in a direcotry. The proposed method in this paper modifies the existing method to make non-admittable ASCII characters for a file name applicable. By improving the existing method, problems of a file creation error due to non-admittable characters are remedied; including the non-admittable 9 characters (i. e. slash /, colon :, greater than >, less than <, question mark ?, back slash ${\backslash}$, vertical bar |, semi-colon ;, esterisk * ), reserved file names(i. e. CON, PRN, AUX, NUL, COM1~COM9, LPT1~LPT9) and two non-admittable characters for an ending character of the file name(i. e. space and dot). Two results of the two message with non-admittable ASCII characters by keyboard inputs show the applicability of the proposed method.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.261-266
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• 2017

This study describes the design and implementation of SHF band Upconverter Digital Satellite Communication. The SHF band Upconverter unit consists of PLDROand frequency converter. In frequency converter, microstripBPF and LPF designed through the pre EMsimulation are implemented to minimize the unwanted spurious in frequency converter. Through the pre-simulation analysis ofspace environment, the possibility of and minimized about the malfunction of equipment and we designed a reliable SHF band Upconverter through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of SHF band Upconverter after production.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1090-1097
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• 2007

The multibeam surveillance radar is a state-of art of 3D radar technology. It applies the stacked beam-on-received realized by a digital beamformer. In this paper, a design concept of beamformer and a method of target altitude extraction for multibeam surveillance radar in the normal environmental condition considering no multipath situations are proposed and investigated. The extraction algorithm based on antenna sine space coordinated system in a FFT digital beamformer is described. The proposed algorithm is simulated by 1 look-up table data and confirmed to have consistent results in accordance with a variety of target altitudes and a full radar frequency range.

• International Commerce and Information Review
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• v.6 no.1
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• pp.249-265
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• 2004

In the current digital age, most of the countries in the world recognize the electronic business to be a very prospective area in the future and plan to activate for the preoccupation of the business. As a result, this led a rapid increase of the electronic business volume. Electronic business takes place in the cyber space, using internet. However, the intellectual property rights have a high degree of possibility of being infringed as the digitalized intellectual property is easy to receive, copy and transmit in the cyber space. The language structure on the web, represented by HTML, makes easier to copy the intellectual property. And, as the internet has no national boundary, the infringement of the intellectual property rights is easier regardless of country, which could lead to the commercial disputes between the concerned countries. There are in fact many legal disputes nowadays on the infringement of the intellectual property rights in such field as computer programming, infringement of the copyright, business model patent and infringement of the trademark right on the registered name of the domain. It is, therefore, time now to prepare a new theory or legal system to protect the intellectual property rights on copyright, patent and trademark right so as to comply with the digital environment together with such a splendid growth of "electronic business." USA and Germany are nowadays making a significant movement on the legislation of the electronic business, and this study will focus on the legislative contents, judicial precedents and interpretation of law in the above countries.