• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.205-215
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• 2002

In this paper the Dynamic Minislot Reservation Protocol(DMRP) in which the control channel is divided into contention-less and contention minislots in order to reduce re-transmission probability in multicasting is proposed. In the network, earth node has two pairs of transceivers. A transceiver consisting of a fixed transmitter and a fixed receiver is used to control packet registration and the other transceiver is used to transmit data. Two types f transceivers for data transmission are considered : one is FT-TR(Fixed Transmitter-Tunable Receiver) and the other is TT-TR(Tunable Transmitter-Tunable Receiver). In the analysis, FT-TR and TT-TR single-hop passive star networks are compared. As results, we conclude that the DMRP protocol with dynamically divided control channel has improved the system performance such as throughput and system delay regardless of traffic type or network structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1474-1480
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• 2011

Recently the mobile IPTV service has been spread through the wireless LAN(WLAN). In order to provide the commercial mobile IPTV service through the WLAN, re-authentication for the mobile IPTV terminal is required whenever the mobile terminal roams between APs(Access Points). The most popular one of the authentication protocol standards for the wired and/or wireless LAN is IEEE 802.1X. However IEEE 802.1X takes much time to authenticate the terminal and is not adequate for the seamless mobile IPTV service. We introduce the session key and separate the user authentication and the hardware authentication. And we strengthen the device authentication by the initial registration. By these, the proposed authentication protocol reduces the authentication time and can protect the authentication key securely.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.4
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• pp.320-325
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• 2010

This paper is about the method and procedure to register the candidate sequentially in the face recognition system using the PCA(Principal Components Analysis). We use the method to update the principal components sequentially with the SKL algorithm which is improved R-SVD algorithm. This algorithm enable us to solve the re-training problem of the increase the candidates number sequentially in the face recognition using the PCA. Also this algorithm can use in robust tracking system with the bright change based to the principal components. This paper proposes the procedure in the face recognition system which sequentially updates the principal components using the SKL algorithm. Then we compared the face recognition performance with the batch procedure for calculating the principal components using the standard KL algorithm and confirms the effects of the forgetting factor in the SKL algorithm experimentally.

• Journal of Korean Library and Information Science Society
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• v.53 no.3
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• pp.119-135
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• 2022

The purpose of this study is to determine whether the pre-evaluation of the feasibility of establishing a public library, which is mandatory according to the revision of the Library Act, can improve the quality of the library. Therefore, the effectiveness of the preliminary evaluation was analyzed through the case analysis of the preliminary evaluation of the public library construction support project, which was implemented for the same purpose before the revision of the Library Act. In the case of libraries built after preliminary evaluation, most of the minimum standards for legal librarians required by the Enforcement Decree of the Library Act were secured, which helped secure basic library personnel. However, there were few libraries that secured and operated as much manpower as originally planned, and in some cases, the application applied to operate the library directly, but it was changed to consignment operation at the time of opening, so the pre-review details were not faithfully reflected. This study proposed re-establishing realistic librarian placement standards according to the revision of the law and introducing a post-evaluation using the library registration system so that it would not be a formal pre-process through case analysis.

• Land and Housing Review
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• v.5 no.1
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• pp.53-56
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• 2014

Hong Kong, a well-known metropolis characterized by skyscrapers on both sides of the Victoria Harbour, consists mainly of 3 parts, namely the Hong Kong Island, the Kowloon peninsula and the New Territories (N.T.) which is the land area north of Kowloon plus a number of outlying islands. Located in the N.T. are all the new towns, market towns; and in the plains and valleys lie scattered village houses of not more than 3 storeys within the confines of well-defined village. These village houses are governed by a rural housing policy that could be traced back to the very beginning of the former British administration in the N.T. By the Convention of Peking of 1898, the N.T., comprising the massive land area north of Kowloon up to Shenzhen River and 235 islands, was leased to Britain by China for 99 years from 1st July 1898. Soon after occupation, the colonial government conducted a survey of this uncharted territory from 1899 to 1903, and set up a land court to facilitate all land registration work and to resolve disputed claims. By 1905, the Block Crown Leases with Schedule of Lessees and details of the lots, each with a copy of the lot index plan (Demarcation Plan) were executed. Based on the above, Crown rent rolls were prepared for record and rent collection purposes. All grants of land thereafter are known as New Grant lots. After completion and execution of the Block Crown Lease in 1905, N.T. villagers had to purchase village house lots by means of Restricted Village Auctions; and Building Licences were issued to convert private agricultural land for building purposes but gradually replaced by Land Exchanges (i.e. to surrender agricultural land for the re-grant of building land) from the early 1960's until introduction of the current Small House Policy in October 1972. It was not until the current New Territories Small House Policy came into effect in December 1972 that the Land Authority can make direct grant of government land or approve the conversion of self-owned agricultural land to allow indigenous villagers to build houses within the village environs under concessionary terms. Such houses are currently restricted to 700 square feet in area and three storeys with a maximum height of 27 feet. An indigenous villager is a male descendent of a villager who was the resident of a recognized village already existing in 1898. Each villager is only allowed one concessionary grant in his lifetime. Upon return of Hong Kong to the People's Republic of China on July 1st, 1997, the traditional rights of indigenous villagers are protected under Article 40 of the Basic Law (a mini-constitution of the Hong Kong Special Administrative Region). Also all N.T. leases have been extended for 50 years up to 2047. Owing to the escalating demand and spiral landed property prices in recent years, abuse of the N.T. Small House Policy has been reported in some areas and is a concern in some quarters. The Hong Kong Institute of Land Administration attempts to study the history that leads to the current rural housing policy in the New Territories with particular emphasis on the small house policy, hoping that some light can be shed on the "way forward" for such a controversial policy.

• Journal of KIISE:Information Networking
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• v.34 no.1
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• pp.62-72
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• 2007

Mobile Virtual Private Network (MVPN) provides VPN services without geographical restriction to mobile workers using mobile devices. Coexistence of Mobile IP (MIP) protocol for mobility and IPsec-based VPN technology are necessary in order to provide continuous VPN service to mobile users. However, Problems like registration failure or frequent IPsec tunnel re-negotiation occur when IPsec-based VPN Gateway (GW) and MIP are used together. In order to solve these problems, IETF proposes a mechanism which uses external home agent (x-HA) located external to the corporate VPN GW. In addition, based on the IETF proposal, a mechanism that assigns x-HA dynamically in the networks where MN is currently located was also proposed with the purpose to reduce handover latency as well as end-to-end delay. However, this mechanism has problems such as exposure of a session key for dynamic Mobility Security Association (MSA) or a long latency in case of the handover between different networks. In this paper, we propose a new MVPN protocol in order to minimize handover latency, enhance the security in key exchange, and to reduce data losses cause by handover. Through a course of simulation, the performance of proposed protocol is compared with the existing mechanism.

• Journal of Korea Multimedia Society
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• v.15 no.6
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• pp.805-813
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• 2012

In this paper, we have designed and developed a middleware for an effectively approaching database to the existed brain disease clinical research system. The brain disease clinical research system was consisted of two parts i.e., a register and an analyzer. Since the register collects the registration data the analyzer yields a statistical data which based on the diverse variables. The middleware has designed to database management and a large data query processing of clients. By separating the function of each feature as a module, the module which was weakened connectivity between functionalities has been implemented the re-use module. And image data module used a new compression method from image to text for an effective management and storage in database. We tested the middleware system using 700 actual clinical medical data. As a result, the total data transmission time was improved maximum 115 times faster than the existing one. Through the improved module structures, it is possible to provide a robust and reliable system operation and enhanced security functionality. In the future, these middleware importances should be increased to the large medical database constructions.

• Progress in Medical Physics
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• v.22 no.3
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• pp.155-162
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• 2011

The analog image based system consisted of a simulator and medical linear accelerator (LINAC) for radiotherapy was upgraded to digital medical image based system by exchanging the X-ray film with Computed Radiography (CR). With minimum equipments shift and similar treatment process, it was possible that the new digital image system was adapted by the users in short time. The film cassette and the film developer device were substituted with a CR cassette and a CR Reader, where the ViewBox was replaced with a small size PC and a monitor. The viewer software suitable for radiotherapy was developed to maximize the benefit of digital image, and as the result the convenience and the effectiveness was improved. It has two windows to display two different images in the same time and equipped various search capability, contouring, window leveling, image resizing, translation, rotation and registration functions. In order to avoid any discontinuance of the treatment while the transition to digital image, the film and the CR was used together for 1 week, and then the film developer was removed. Since then the CR System has been operated stably for 2 months, and the various requests from users have been reflected to improve the system.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.166-171
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• 2010

Purpose: The SPECT/CT is able to acquire diagnostic information resolved the difficult problems that discriminate regions of focals by intergrating functional images and anatomical images. We introduce the usefulness of "Volumetrix Suite" which can describe 3D images by the convergence of the SPECT/CT images and reference CT images. Materials and Methods: We applied Volumetrix Suite program (Volumetrix IR, Volumetrix 3D) to patients, Bone, Venography, Parathyroid, WBC, taken diagnostic CT examination which have same regions of focal in Seoul Metropolitan Government Seoul National University Boramae Medical Center. After acquiring SPECT/CT images and reference CT images, we fused a couple of scans applying for this programs. The CT scan of Infinia Hawkeye 4 shows limitation of anatomical information. For this reason, we tried to transfer CT images that have lots of diagnostic informations as the form of Dicom file in PACS, and changed from 2D images to 3D images after image registering in Xeleris Workstaion of Hawkeye 4. Results & Conclusion: By using Volumetrix Suite program, we're able to acquire more accurate anatomical informations with 3D rendering which can distinguish both location and range of focals in Infinia Hawkeye 4. Thus, the result of utilizing this program indicate that nuclear medicine anatomical images can be improved by providing more diagnostic imformations produced by its program.

• Journal of Radiation Protection and Research
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• v.33 no.2
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• pp.47-51
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• 2008

Objective: This study analyzed errors due to rotation or tilt of the magnetic resonance (MR) imaging indicator during image acquisition for a stereotactic radiosurgery. The error correction procedure of a commercially available stereotactic neurosurgery treatment planning program has been verified. Materials and Methods: Software virtual phantoms were built with stereotactic images generated by a commercial programming language, Interactive Data Language (version 5.5). The thickness of an image slice was 0.5 mm, pixel size was $0.5{\times}0.5mm$, field of view was 256 mm, and image resolution was $512{\times}512$. The images were generated under the DICOM 3.0 standard in order to be used with Leksell GammaPlan$^{(R)}$. For the verification of the rotation error correction function of Leksell GammaPlan$^{(R)}$, 45 measurement points were arranged in five axial planes. On each axial plane, there were nine measurement points along a square of length 100 mm. The center of the square was located on the z-axis and a measurement point was on the z-axis, too. Five axial planes were placed at z=-50.0, -30.0, 0.0, 30.0, 50.0 mm, respectively. The virtual phantom was rotated by $3^{\circ}$ around one of x, y, and z-axis. It was also rotated by $3^{\circ}$ around two axes of x, y, and z-axis, and rotated by $3^{\circ}$ along all three axes. The errors in the position of rotated measurement points were measured with Leksell GammaPlan$^{(R)}$ and the correction function was verified. Results: The image registration errors of the virtual phantom images was $0.1{\pm}0.1mm$ and it was within the requirement of stereotactic images. The maximum theoretical errors in position of measurement points were 2.6 mm for a rotation around one axis, 3.7 mm for a rotation around two axes, and 4.5 mm for a rotation around three axes. The measured errors in position was $0.1{\pm}0.1mm$ for a rotation around single axis, $0.2{\pm}0.2mm$ for double and triple axes. These small errors verified that the rotation error correction function of Leksell GammaPlan$^{(R)}$ is working fine. Conclusion: A virtual phantom was built to verify software functions of stereotactic neurosurgery treatment planning program. The error correction function of a commercial treatment planning program worked within nominal error range. The virtual phantom of this study can be applied in many other fields to verify various functions of treatment planning programs.