• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.1
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• pp.64-77
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• 2009

A proxy re-encryption scheme allows Alice to temporarily delegate the decryption rights to Bob via a proxy. Alice gives the proxy a re-encryption key so that the proxy can convert a ciphertext for Alice into the ciphertext for Bob. Recently, ID-based proxy re-encryption schemes are receiving considerable attention for a variety of applications such as distributed storage, DRM, and email-forwarding system. And a non-interactive identity-based proxy re-encryption scheme was proposed for achieving CCA-security by Green and Ateniese. In the paper, we show that the identity-based proxy re-encryption scheme is unfortunately vulnerable to a collusion attack. The collusion of a proxy and a malicious user enables two parties to derive other honest users' private keys and thereby decrypt ciphertexts intended for only the honest user. To solve this problem, we propose two ID-based proxy re-encryption scheme schemes, which are proved secure under CPA and CCA in the random oracle model. For achieving CCA-security, we present self-authentication tag based on short signature. Important features of proposed scheme is that ciphertext structure is preserved after the ciphertext is re-encrypted. Therefore it does not lead to ciphertext expansion. And there is no limitation on the number of re-encryption.

• Journal of IKEEE
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• v.24 no.2
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• pp.638-648
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• 2020

Currently, the method of user-follwoing in intelligent cooperative robots usually based in vision system and using Lidar is common and have excellent performance. But in the closed space of Corona 19, which spread worldwide in 2020, robots for cooperation with medical staff were insignificant. This is because Medical staff are all wearing protective clothing to prevent virus infection, which is not easy to apply with existing research techniques. Therefore, in order to solve these problems in this paper, the ultrasonic sensor is separated from the transmitting and receiving parts, and based on this, this paper propose that estimating the user's position and can actively follow and cooperate with people. However, the ultrasonic sensors were partially applied by improving the Median filter in order to reduce the error caused by the short circuit in communication between hard reflection and the number of light reflections, and the operation technology was improved by applying the curvature trajectory for smooth operation in a small area. Median filter reduced the error of degree and distance by 70%, vehicle running stability was verified through the training course such as 'S' and '8' in the result.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.1
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• pp.42-52
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• 2012

In this paper, a waveguide antenna is designed and fabricated for side and rear radar sensor of vehicles in UWB (Ultra Wide Band) high band (center frequency : 9.5 GHz, -10 dB bandwidth : 600 MHz (6.4 %)). For the radar antenna, a probe fed rectangular waveguide antenna having simple structure and wide bandwidth is used. An important performance factor in this antenna is the isolation between transmitting (TX) and receiving (RX) waveguide antennas because this radar system uses TX and RX antennas separately. Thus the isolation between two antennas was simulated for E-plane and H-plane array. As a result, it was verified that the isolation of the H-plane array of the antennas is better than E-plane array, due to the TE10 mode. Therefore, H-plane arrayed waveguide antennas were mounted on a T-shaped radar module and performance of antennas was investigated. The -10 dB bandwidth of the TX and RX antenna mounted on T-shaped radar module was measured as 1000 MHz (10.52 %) and 1090 MHz (11.47 %) respectively and the isolation is less than -50 dB in the operation band. The peak gain is 7.65 dBi for the TX antenna and 7.26 dBi for the RX antenna and the beamwidth of H-plane of TX and RX antenna was measured as $64^{\circ}$ and $65^{\circ}$ respectively. Consequently, we verified that the proposed waveguide antenna is appropriate for a vehicle radar applications.

• Korean Journal of Optics and Photonics
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• v.10 no.6
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• pp.500-506
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• 1999

We designed and fabricated a bidirectional optical transceiver module for low cost access network. An integrated chip forming a pin-PD on an 1.3 urn FP-LD was assembled by flip-chip bonding on a Si optical bench, a single mode fiber with an angled end facet was aligned passively with the integrated chip on V-groove of Si-optical bench. Gaussian beam theory was applied to evaluate the coupling coefficients as a function of some parameters such as alignment distance, angle of fiber end facet, vertical alignment error. The theory is also used to search the bottle-neck between transmittance and receiving coupling efficiency in the bi-directional optical system. Tn this paper, we confirmed that reduction of coupling efficiency by the vertical alignment error between laser beam and fiber core axis can be compensated by controlling the fiber facet angle. In the fabrication of sub-module, a'||'&'||' we made such that the fiber facet have a corn shape with an angled facet only core part, the reflection of transmitted laser beam from the fiber facet could be minimized below -35 dE in alignment distance of 2: 30 /J.m. In the same condition, transmitted output power of -12.1 dEm and responsivity of 0.2. AIW were obtained.

• Journal of Korean society of Dental Hygiene
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• v.9 no.4
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• pp.699-714
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• 2009

Objectives : This study was to examine factors affecting the job satisfaction of dental hygienists. Methods : The subjects in this study were dental hygienists who worked at dental hospitals, dental clinics and general hospitals in the city of Gwangju. A survey was conducted by mail from January 2 to March 2, 2007. Out of the collected data, 208 answer sheets were analyzed. Results : 1. The dental hygienists investigated got a mean of 3.20 on job satisfaction. Among the job satisfaction factors, relationship with patients ranked highest(3.79), followed by relationship with colleagues(3.62), working environments(3.39), future prospects(3.30), professional status (2.89), pay(2.82) and required workload(2.58). 2. Regarding links between general characteristics and job satisfaction, the older dental hygienists were more satisfied with professional status, pay, required workload and relationship with patients. By marital status, the married dental hygienists expressed better satisfaction at professional status than the unmarried ones. By education, those who were receiving college education or received the same or higher education were more gratified than the junior college graduates. By the total length of career, the dental hygienists whose length of career was longer were more gratified with professional status, future prospects and relationship with patients. By workplace, the dental hospital workers were more satisfied with working environments, and the general hospital employees were more gratified with pay. The dental hospital employees were better satisfied with future prospects as well. As to the impact of the length of career at the current workplace, there was a tendency that those who worked at their current workplaces for a longer time expressed better satisfaction with professional status, pay and relationship with patients. By monthly mean income, the larger income earners had a tendency to be better gratified with professional status, pay and relationship with patients. 3. The general characteristics that were selected as independent variables were identified as the factors that exercised an influence on the job satisfaction of the dental hygienists and made an about 14.0% prediction of it. Out of those factors, the total length of career and monthly mean income had a statistically significant impact on that. Conclusions : The above-mentioned findings suggested that out of the seven job satisfaction components, they gave the lowest marks to satisfaction level with pay. As a result of making a multiple regression analysis, it's found that job satisfaction was under the influence of the total length of career and monthly mean income. Therefore there should be an improvement in the pay system in order to boost the job satisfaction of dental hygienists, and they should be paid properly in accordance with total length of career.

• The Korean Society of Law and Medicine
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• v.14 no.1
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• pp.355-401
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• 2013

The first legislation for terminal health-care decision was California's Natural Death Act (NDA) of 1976 that permitted any adult person to execute a directive directing the withholding or withdrawal of life-sustaining procedures. Advance directive legislation has subsequently progressed on a state-by-state basis. By 1992, all 50 states, as well as the District of Columbia, had passed legislation to legalize some form of advance directive. This state legislation, however, has resulted in an often fragmented, incomplete, and sometimes inconsistent set of rules. Statutes enacted within a state often conflict and conflicts between statutes of different states are common. In an increasingly mobile society where an advance health-care directive given in one state must frequently be implemented in another, there is a need for greater uniformity. In 1993, the Uniform Law Commissioners approved the Uniform Health-Care Decisions Act (UHCDA) in order to bring order to the existing chaos. Unfortunately, the Commissioners waited too long to act. By the time the UHCDA was approved, nearly all states had passed legislation governing advance directives. Consequently, the UHCDA has achieved only a limited success, picking up but one or two enactments a year. The UHCDA is currently in effect in around 10 states: Alabama, Alaska, California, Delaware, Hawaii, Kansas, Maine, Mississippi, New Mexico, Tennessee, Wyoming. In these states the previous laws related to the subjects have been all repealed. The overall objective of the UHCDA is to encourage the making and enforcement of advance health care directives including living will or individual instruction, power of health-care attorney and to provide a means for making health care decisions for those who have failed to plan. The U. S. House of Representatives in 1991 enacted the Patient Self-Determination Act (PSDA). The Act stipulates that all hospitals receiving Medicaid or Medicare reimbursement must ascertain whether patients have or wish to have advance directives. The Patient Self- Determination Act does not create or legalize advance directives; rather it validates their existence in each of the states. Now in America, terminal health-care decision or advance directive for health care is common and universal system. The problem, however, is how to let more people use these good tools to make their lives more beautiful and honorable.

• Radiation Oncology Journal
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• v.30 no.3
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• pp.132-139
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• 2012

Purpose: The purpose of this prospective multi-institutional study was to evaluate the nutritional status of patients undergoing radiotherapy (RT) for treatment of head and neck, lung, or gastrointestinal cancer. Materials and Methods: A total of 1,000 patients were enrolled in this study at seven different hospitals in Seoul, Korea between October 2009 and May 2010. The nutritional status of patients after receiving 3 weeks of RT was evaluated using subjective global assessment (SGA). The nutritional status of each patient was rated as well nourished (A), moderately malnourished (B), or severely malnourished (C). Results: The mean age of patients in this study was $59.4{\pm}11.9$ years, and the male to female ratio was 7:3. According to the SGA results, 60.8%, 34.5%, and 4.7% of patients were classified as A, B, or C, respectively. The following criteria were significantly associated with malnutrition (SGA B or C; p < 0.001): loss of subcutaneous fat or muscle wasting (odds ratio [OR], 11.473); increased metabolic demand/stress (OR, 8.688); ankle, sacral edema, or ascites (OR, 3.234); and weight loss ${\geq}5%$ (OR, 2.299). Conclusion: SGA was applied successfully to assess the nutritional status of most patients. The prevalence of malnutrition in a radiation oncology department was 39.2%. The results of this study serve as a basis for implementation of nutrition intervention to patients being treated at radiation oncology departments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.6
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• pp.788-801
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• 1998

Meteor Burst Communication can provide effective and economical means of communication where long distance VHF NLOS data transmission is needed ; often ranges more than 1000 km. It has been, however, so far considered unsuitable for short distance application because of phenomenal decrease in burst durations, which leads to decreation of total duty rate of the system. This paper extensively analyzes characteristics of shot distance MB(Meteor Burst) path and shows the low duty rate may be improved by increasing burst rate through adapting antennal beam width to cover entire hot-spot region in the space and, by compensating effective burst length throughcutting down man-made noises introduced by antennal. Based on the analysis, we are developed a small-opening-cavity antennal, especially designed for short distance MB path. In operation, the antenna is to be buried under ground surface so as to improve directivity and reduces noise introduction. The antennal exhibits power gain of 3 dB with 90 degree beam width and thus enables to illuminate entire hot-spot regions with the elevation angle of 8-90 degree which is the case of transmission less than 100 km. Directivity horizontal to earth surface is suppressed to minimum which enables to cut man-made noises from near-by sources down to more than 3 dB from the level reported with conventional 4 element Yagi. A series of experiments performed on 100km MB paths have conformed that, with the antenna installed at receiving site, the burst rate and duration time have been noticed to increase by 10 and 20 percent respectively from the values obtained by conventional 4-element Yagi antennal under same testing condition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.6
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• pp.613-622
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• 2013

In this paper, an inductive clamping class-E power amplifier has been tested for wireless power transmission at ISM band, 13.56 MHz. The implemented power amplifier is designed to operate stably without destroying power transistor in wireless power transmission system which basically keeps not to align between a transmitting antenna and a receiving antenna. The power amplifier is also designed to enhance harmonic filtering characteristic. The amplifier was tested with a DC supply voltage of 28 V and input power of 25 dBm at 13.56 MHz. The test results show the output power level of 43 dBm, the difference power level between fundamental frequency and second harmonic frequency of more than 55 dBc, the dc current consumption of 830 mA, and the high power-added efficiency of 85 %. Finally, the implemented power amplifier operated normally with 830 mA DC current consumption from 28 V source when the two antennas were aligned, and the power transmission was successful. But when the two antennas were not aligned, its DC current consumption automatically decreased down to 420 mA to protect the switching transistor.

• Journal of Information Technology and Architecture
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• v.9 no.2
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• pp.155-166
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• 2012

Recently EA(Enterprise Architecture) has been receiving growing attentions again from the public sectors. It is because EA maturity result is reflected to the organization's informatization level and EA maturity ratio has been enlarged. There has been more participation from the Chief Information Officers of the public sectors. EA research in the public sectors has influenced IT environment since the research started in late '90, the legislation work done in '05, and the maturity model developed in '06. However, there are some remaining tasks to solve. EA policy is introduction oriented, its contribution to the consecutive the best UN e-Government rank is limited, and its user-friendly responding system is still lacking. Related research outcomes are rather microscopic focusing only on the models and maturity than implicating on the public policy in a macroscopic manner. In this respect, this study will provide the implication on how EA policy should be. Requirements derived from EA stakeholders and the tasks will be arranged in accordance with its domain, then the performance and tasks will be demonstrated. As guiding EA stake holders and information related officers to setup the EA policy with these results, this study is expected to support information the policy drivers.