• Journal of Communications and Networks
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• v.11 no.2
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• pp.148-156
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• 2009

The fixed spectrum assignment policy in today's wireless networks leads to inefficient spectrum usage. Cognitive radio network is a new communication paradigm that enables the unlicensed users to opportunistically use the spatio-temporally unoccupied portions of the spectrum, and hence realizing a dynamic spectrum access (DSA) methodology. Interference temperature model proposed by Federal Communications Commission (FCC) permits the unlicensed users to utilize the licensed frequencies simultaneously with the primary users provided that they adhere to the interference temperature constraints. In this paper, we formulate two NP-hard optimal scheduling methods that meet the interference temperature constraints for cognitive radio networks. The first one maximizes the network throughput, whereas the second one minimizes the scheduling delay. Furthermore, we also propose suboptimal schedulers with linear complexity, referred to as maximum frequency selection (MFS) and probabilistic frequency selection (PFS). We simulate the throughput and delay performance of the optimal as well as the suboptimal schedulers for varying number of cognitive nodes, number of primary neighbors for each cognitive node, and interference temperature limits for the frequencies. We also evaluate the performance of our proposed schedulers under both additive white gaussian noise (AWGN) channels and Gilbert-Elliot fading channels.

• Smart Media Journal
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• v.1 no.1
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• pp.17-26
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• 2012

In cognitive radio networks (CRNs), unlicensed users sense the licensed spectrum bands and opportunistically access them without interfering operations of licensed users. Especially, in ad hoc networks, the MAC layer plays an important role in coordinating unlicensed users access to the spectrum and, thus, a number of MAC protocols have been studied recently. In this paper, we comparatively examine MAC protocols in cognitive radio ad hoc networks (CRAHNs). First, we categorize the protocols on the basis of common control channel (CCC) requirements and further review major implementations for each category. Then, we make a qualitative comparison of the protocols in terms of inherent characteristics and performance.

• The Korean Society of Law and Medicine
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• v.15 no.1
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• pp.11-34
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• 2014

Promulgation of the medical practice rule without specific definition in Medical Law has brought about many constitutional issues. The major issue is that the law has the government punish unlicensed medical practice without defining what it is. Instead, the law chooses a license-centered structure of criminal punishment for medical malpractice, saying "no one can practice medicine without the government-approved license." This regulation violates the rule of "void for vagueness" based on the principle of "nulla poena nullum crimen sine lege." Judicial interpretation should be required for a citizen to understand the Medical Law provision intuitively. In addition, the law infringes upon the freedom of occupation of the unlicensed and the licensed who wish to extend his or her practice area for "holistic medicine." The central issue of the law is that it was established under no ground of professionalism even though medical practice has been understood professional. The government has centrally controlled the medical field for its needs. Lastly, the current law violates the right of medical selection of the consumers of medicine. Because patients have the right of health and life, they have to hold the latitude of selection for medical treatments. Especially, they should have an opportunity for considering the Complementary and Alternative Medicine if they want. But under the current rules, this medicine is not permitted. To correct those problems, a new provision for the definition of medical practice should be adopted at once.

• Journal of Korean society of Dental Hygiene
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• v.13 no.2
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• pp.211-220
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• 2013

Objectives : This study intended to figure out illegal treatment by unlicensed person in dental area and factors, which were considered as user's position on the basis of the local community investigation of health conditions in chungbuk provinces in 2008. Methods : This study used chi-square test and complex sample design of multi-variate logistic regression analysis to question 12,443 peoples who have experience on illegal dental treatment. Results : Multi-variate logistic regression analysis results showed that factors having related to illegal dental treatment are sex, age, education standards, subjective awareness of oral health condition, drinking experience of lifetime, unmet need of dental treatment, chewing difficulty, use of dentures, experience of scaling and the use of interdental care instrument. Conclusions : As a result of this study, in order to root out illegal dental treatment, we need to expand the breadth of health insurance coverage so that it can reduce the burden of dental expenses. Moreover, we need to set out health service of public oral health to inform the importances of maintaining good oral health and the problems of illegal dental treatment by unlicensed person.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.5
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• pp.1532-1553
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• 2014

Radio spectrum is a precious resource and characterized by fixed allocation policy. However, a large portion of the allocated radio spectrum is underutilized. Conversely, the rapid development of ubiquitous wireless technologies increases the demand for radio spectrum. Cognitive Radio (CR) methodologies have been introduced as a promising approach in detecting the white spaces, allowing the unlicensed users to use the licensed spectrum thus realizing Dynamic Spectrum Access (DSA) in an effective manner. This paper proposes a generalized framework for DSA between the licensed (primary) and unlicensed (secondary) users based on Continuous Time Markov Chain (CTMC) model. We present a spectrum access scheme in the presence of sensing errors based on CTMC which aims to attain optimum spectrum access probabilities for the secondary users. The primary user occupancy is identified by spectrum sensing algorithms and the sensing errors are captured in the form of false alarm and mis-detection. Simulation results show the effectiveness of the proposed spectrum access scheme in terms of the throughput attained by the secondary users, throughput optimization using optimum access probabilities, probability of interference with increasing number of secondary users. The efficacy of the algorithm is analyzed for both imperfect spectrum sensing and perfect spectrum sensing.

• The Korean Journal of Emergency Medical Services
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• v.25 no.2
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• pp.169-186
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• 2021

Purpose: This study aimed to analyze the data from public information disclosure about pre-hospital advanced airway management and identify the problem by considering domestic laws and guidelines. Methods: Data were collected between 2017 and 2018 and analyzed using SPSS 25.0. Then, the problems of the analysis results based on the relevant laws and practical guidelines were reviewed. Results: The review of domestic laws and practice guidelines revealed that ambulance nurses can implement supraglottic airway device only under the following three conditions: ① smart advanced life support pilot project area, ② trained to insert I-Gel, and ③ member of a special ambulance. In total, 21,574 cases of advanced airway management (endotracheal intubation: 2,428, I-Gel: 18,502, LMA : 499, KING AIRWAY: 144) were reported. In many cases, advanced airway management was performed by ambulance nurses who did not meet the above conditions, which was in violation of laws and guidelines. In addition, the prognosis of intubated patients was not followed up. Conclusion: The Korea National Fire Agency must stop all unlicensed medical practice by untrained, uneducated, and uncertified nurses and demand quality control programs for intubated patients.

• ETRI Journal
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• v.43 no.1
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• pp.7-16
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• 2021

Noncontiguous orthogonal frequency division multiplexing (NC-OFDM)-based cognitive radio (CR) systems achieve highly efficient spectrum utilization by transmitting unlicensed users' data on subcarriers of licensed users' data when they are free. However, there are two disadvantages to the NC-OFDM system: out-of-band power (OBP) and a high peak-to-average power ratio (PAPR). OBP arises due to side lobes of an NC-OFDM signal in the frequency domain, and it interferes with the spectrum for unlicensed users. A high PAPR occurs due to the inverse fast Fourier transform (IFFT) block used in an NC-OFDM system, and it induces nonlinear effects in power amplifiers. In this study, we propose an algorithm called "Alternative Projections onto Convex and Non-Convex Sets" that reduces the OBP and PAPR simultaneously. The alternate projections are performed onto these sets to form an iteration, and it converges to the specified limits of in-band-power, peak amplitude, and OBP. Furthermore, simulations show that the bit error rate performance is not degraded while reducing OBP and PAPR.

• The Korean Society of Law and Medicine
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• v.24 no.1
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• pp.3-42
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• 2023

The Supreme Court en banc decision on December 12, 2022 (docket number 2016Do21314) ruled that the diagnosis of endometrial hyperplasia by an oriental medical doctor using a diagnostic ultrasound device was not an unlicensed medical practice for an oriental medical doctor, which shall be scrutinized by the article 27 (1) of the Korean Medical Service Act. This ruling did not determine that a specific medical practice, especially diagnosis, based on the radiology, which is a part of western medicine, was not an unlicensed medical practice for an oriental medical doctor. Rather, it intended to clarify that the prosecutor should specify and prove the way of diagnosis and he should not prosecute mere the use of a diagnostic ultrasound device itself. To that extent, the ruling is agreeable because, as the oriental medicine community has argued, there is no regulation prohibiting the use of certain devices. It is probable, however, that the way of diagnosis established in radiology, which is a part of western medicine, was actually used in the case. In that case, there is undeniably an unlicensed medical practice for an oriental medical doctor. While many of the cases where the demarcation between (western) medicine and oriental medicine have been problematized thus far have been experimental treatment in nature, the above practice of using ultrasound appears to be frequently done in many oriental clinics, and so it is necessary to cope with the possibility of a disguised unlicensed medical practice. Another problem is the prevention of unfair practice or the protection of medical consumers. In fact, many oriental medical clinics' practice appear to have a tendency of inducing medical consumers' misunderstanding that a diagnosis based on radiology, which is a part of western medicine, were provided. It is hard to respond to this problem with demarcation between (western) medicine and oriental medicine. A new regulation against unfair practice might be necessary to implement.

• Journal of Technologic Dentistry
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• v.34 no.4
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• pp.433-445
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• 2012

Purpose: In order to validate empirically the theoretical model of this study subjects, who were limited in Andong gun, Youngyang gun, Uiseong gun, Bonghwa gun, Chilgok gun, Cheongsong gun according to residence-specified distribution and over aged 65, were focused to the elderly in rural areas with geographical characteristics where they have difficulties in accessibility of dental facilities and dental care. Methods: The collected data were analyzed by the SPSS 19.0 program. First, the frequency analysis was performed for each independent variable and the dependent variable. Second, reliability analysis and correlation analysis were conducted for daily living skills and Biomedical Vigilance. Third, multivariate analysis was performed in terms of and the post-administration management. Fourth, multiple regression analysis was performed to identify the factors affecting the post-management of dentures and the period of using dentures. Results: By results of the multiple regression analysis, the elder the subjects are(${\beta}$ = 0.03), the lower their income activities are(${\beta}$ = -0.18), the smaller their monthly allowances are(${\beta}$ = -0.16), the worse their daily activity skills are(${\beta}$ = -0.12), the more they were mounted their dentures by an unlicensed contractor(${\beta}$ = 0.07), and the more they cost to their dentures(${\beta}$ = 0.14), the longer the period of use dentures are. And the beneficiaries of Basic Livelihood Security(${\beta}$ = -0.14) who got free denture business are shorten the period of using dentures. According to multiple regression analysis for post management of dentures, the independent variables like the health education(${\beta}$ = 0.24), smoking(${\beta}$ = -0.18), periodic oral examination(${\beta}$ = 0.13), dentures mounted by an unlicensed contractor(${\beta}$ = -0.13) are shown statistically significant results. In that study subjects are taking part in health education and non-smokers, they are likely to have more chances to post management for their dentures like periodic oral examination. However the subjects who were weared their denture by an unlicensed contractor get less chance to post management for their dentures. Conclusion: As the elderly who want to wear denture are increasing due to the denture insurance for the elderly, the need for oral health education for the elderly is an urgent request, especially continuos education for the way of use their dentures and follow-up management for the elderly who were already mounted their dentures. And also, the need for more systematic researches is requested for securing objective data.

• Journal of Communications and Networks
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• v.5 no.4
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• pp.290-302
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• 2003

Ultra wide band (UWB) radio has recently attracted increased attention due to its expected unlicensed operation, and potential to provide very high data rates at relatively short ranges. In this article we briefly describe some main candidate multiple access and modulation schemes for UWB communications, followed with their power spectral density calculation and properties. We also present some illustrative capacity results, and provide a discussion of the impact of network topology on multiple access capacity.