• Title/Summary/Keyword: Primary Users

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Improved Resource Allocation Model for Reducing Interference among Secondary Users in TV White Space for Broadband Services

  • Marco P. Mwaimu;Mike Majham;Ronoh Kennedy;Kisangiri Michael;Ramadhani Sinde
    • International Journal of Computer Science & Network Security
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    • v.23 no.4
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    • pp.55-68
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    • 2023
  • In recent years, the Television White Space (TVWS) has attracted the interest of many researchers due to its propagation characteristics obtainable between 470MHz and 790MHz spectrum bands. The plenty of unused channels in the TV spectrum allows the secondary users (SUs) to use the channels for broadband services especially in rural areas. However, when the number of SUs increases in the TVWS wireless network the aggregate interference also increases. Aggregate interferences are the combined harmful interferences that can include both co-channel and adjacent interferences. The aggregate interference on the side of Primary Users (PUs) has been extensively scrutinized. Therefore, resource allocation (power and spectrum) is crucial when designing the TVWS network to avoid interferences from Secondary Users (SUs) to PUs and among SUs themselves. This paper proposes a model to improve the resource allocation for reducing the aggregate interface among SUs for broadband services in rural areas. The proposed model uses joint power and spectrum hybrid Firefly algorithm (FA), Genetic algorithm (GA), and Particle Swarm Optimization algorithm (PSO) which is considered the Co-channel interference (CCI) and Adjacent Channel Interference (ACI). The algorithm is integrated with the admission control algorithm so that; there is a possibility to remove some of the SUs in the TVWS network whenever the SINR threshold for SUs and PU are not met. We considered the infeasible system whereby all SUs and PU may not be supported simultaneously. Therefore, we proposed a joint spectrum and power allocation with an admission control algorithm whose better complexity and performance than the ones which have been proposed in the existing algorithms in the literature. The performance of the proposed algorithm is compared using the metrics such as sum throughput, PU SINR, algorithm running time and SU SINR less than threshold and the results show that the PSOFAGA with ELGR admission control algorithm has best performance compared to GA, PSO, FA, and FAGAPSO algorithms.

Effectiveness of Virtual Human Disclosure: The Impact of Identity Exposure on Users' Attitude Toward the Ad and Source Credibility (가상 인간의 정체성 노출이 소비자의 광고 태도와 정보원 공신력에 미치는 영향)

  • Young Jun Sohn;Yoonhyuk Jung
    • Information Systems Review
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    • v.25 no.2
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    • pp.205-227
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    • 2023
  • Recently, Virtual Human(VH) has begun to appear in various media, not only on social media, but also in advertisements, music sources, and dramas. Virtual human has become a primary marketing tool for companies, but there also exist concerns when the companies do not disclose the identities of virtual humans. Accordingly, it is necessary to examine users' responses toward content that features virtual humans. This study aimed to examine how the exposure of virtual humans in the content affects users' perceptions. Therefore, the study defined the concept of 'VH Disclosure(VHD)', referring to the exposure of the virtual human's identity, and explored the impact of VH disclosure on attitude toward the ad (Hedonism, Utilitarianism, and Interestingness) and source credibility (Trustworthiness and Expertise). The study conducted an experimental survey with 302 respondents. Regardless of when the ad featured a VH or a human, the results showed that there was no significant difference between users' attitudes and source credibility. The results revealed that it was more effective to disclose the VH in social media feeds than directly reveal the VH's identity in the content. Therefore, this study utilizes a new concept of 'VH Disclosure(VHD)' to enhance the understanding of VH and contributes to establishing marketing strategies optimized for consumers in the creation of virtual human-related content.

A Study on Sickness and Utilization of Medical Care in a Rural Area of Kyunggido (일부(一部) 농어촌주민(農漁村住民)의 상병(傷病) 및 의료이용도(醫療利用度)에 관(關)한 조사연구(調査硏究))

  • Chang, Yong-Tae
    • Journal of Preventive Medicine and Public Health
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    • v.9 no.1
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    • pp.139-146
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    • 1976
  • This survey attempted to determine the overall health situation in Kyunggido in terms of sickness prevalence, sickness distribution, demand for medical care by type, and utilization of medical care. The survey was conducted on 766 households, or 4,065 people, from July 1-31, 1975. The findings from the survey are as follows: 1) In terms of age distribution, 28.7% of the sample was from 10-19, the 40-49 age group was the next largest group, and those over 60 made up 7% of the sample. 2. The education distribution is as follows, 30.4% completed primary school, 22.4% had no formal education, 20.6% attended but did not onplete primary school, and 1.8% attended unversities or higher. 3) In terms of occupation, 55.9% were unemployed or family employees, which represents a large dependent population, 30.4% of the workers were employed in farming or fisheries. 4. The marital status is as follows, 58.8% of the women were married, 32.3% unmarried, and 7.5% divorced. 5) The prevalence rate of mouthy illness was 19.7% of 100 infant, 42.8% became fatally ill within the first year of life. This is a very high percentage compared with more developed nations. 6) Of those reportion on illness, 54.6% sought treatment. The rate of treatment was highest in infants at 77.7%. Us age increased, demand for treatment decreased to 43.1% for those in the aldest age group. The oldest age group also had the highest rate of non treatment at 56.8%. 7) The demand for medical care showed that 65.6% utilized drug stores, 20.2% utilized hospitals and clinics, 5.4% used herbdrug-stores and herb clinices, and 3.9% relied upon folk medicine and withch craft. 8) The utilization of medical facilties by sex is as follows, 65.1% of the men and 66.0% of the women used drug stores, and 19.2% of the men and 20.2% of the women used hospitals and clinics. However, more men (3.5%) were hospitalized than women (1.8%) 9) In terms of out-patient care, the largest age group of males was 10-19 (28.2%), and the largest age group of females was 0-9 (30.8%). There was no sex difference in the use of western pharmacies. Menaged 30-39 and women aged 50-59 were the most frequent users of herb clinics. 10) The rate of receiving treatment at drugstore hospitals went towards declining level in the second case of what While increaing much more at herb clinics and folk medicines in the second case than the first one. 11) After primary utilization of hospitals, 32.7%. of the adults aged 20-59 used drug-stores as a secondary source of care, and 12.8% of children and youth under age 20 continued receiving care at hospitals. 12) After primary utilization of drug-stores, 32.5 % of the adults continued to seek care at drug stores and 1.8% used hospitals. 4.2% of those over age 60 utilized folk medcine and witch craft.

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A Study on Determining Archiving Priorities of Primary and Secondary Educational Resources (초·중등 교육자원 아카이브 구축을 위한 자원의 우선순위 선정에 관한 연구)

  • Kim, Seonghun;Do, Suelki;Oh, Sam G.
    • Journal of the Korean Society for information Management
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    • v.36 no.2
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    • pp.153-174
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    • 2019
  • This study was conducted to find out basic facts on educational resources in Korea and see how educators have managed their tasks without educational resource archives. The research had the following steps: 1) finding out how the current state of primary and secondary education resources is managed and type of educational resources via Web search and literature review, 2) conducting a survey to determine archiving priorities according to the value of resources to the users, and 3) engaging in a discussion with experts on merits of establishing an educational resource archive system. Due to sporadic management and restricted use of educational resources produced in Korea, the primary and secondary education resources are not easily available to the public even though the public and private sectors produce significant amount of resources. The survey result on preferred educational resource types for archiving showed the following top three: 1) actual case studies conducted in the field, 2) curriculum related resources, and 3) various textbooks adopted. Considering the value of educational resources and the necessity of archiving agencies, the experts recommended to set up a national archiving system of educational resources. This study hopes to raise awareness of the need to set up educational resource archives as a start.

System Throughput of Cognitive Radio Multi-hop Relay Networks (무선인지 멀티홉 릴레이 네트워크의 시스템 스루풋)

  • Hassan, I.;Rho, Chang-Bae;Song, Ju-Bin
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.4
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    • pp.29-39
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    • 2009
  • The need for radio spectrum is recently considered as a huge hurdle towards the rapid development of wireless networks. Large parts of the spectrum are allocated to licensed radio services in proprietary way. However, enormous success of the wireless services and technologies in the unlicensed bands has brought new ideas and innovations. In recent years cognitive radio has gained much attention for solving the spectrum scarcity problem. It changes the way spectrum is regulated so that more efficient spectrum utilization is possible. Multi-hop relay technology on the other hand has intensively been studied in the area of ad hoc and peer-to-peer networks. But in cellular network, only recently the integration of multi-hop capability is considered to enhance the performance significantly. Multi-hop relaying can extend the coverage of the cell to provide high data rate service to a greater distance and in the shadowed regions. Very few papers still exist that combine these methods to maximize the spectrum utilization. Thus we propose a network architecture combining these two technologies in a way to maximize the system throughput. We present the throughput capacity equations for the proposed system model considering various system parameters like utilization factor by the primary users and primary users' transmission radius and through extensive numerical simulations we analyze the significance of work.

Performance Analysis of the Amplify-and-Forward Scheme under Interference Constraint and Physical Layer Security (물리 계층 보안과 간섭 제약 환경에서 증폭 후 전송 기법의 성능 분석)

  • Pham, Ngoc Son;Kong, Hyung-Yun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.1
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    • pp.179-187
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    • 2014
  • The underlay protocol is a cognitive radio method in which secondary or cognitive users use the same frequency without affecting the quality of service (QoS) for the primary users. In addition, because of the broadcast characteristics of the wireless environment, some nodes, which are called eavesdropper nodes, want to illegally receive information that is intended for other communication links. Hence, Physical Layer Security is applied considering the achievable secrecy rate (ASR) to prevent this from happening. In this paper, a performance analysis of the amplify-and-forward scheme under an interference constraint and Physical Layer Security is investigated in the cooperative communication mode. In this model, the relays use an amplify-and- forward method to help transmit signals from a source to a destination. The best relay is chosen using an opportunistic relay selection method, which is based on the end-to-end ASR. The system performance is evaluated in terms of the outage probability of the ASR. The lower and upper bounds of this probability, based on the global statistical channel state information (CSI), are derived in closed form. Our simulation results show that the system performance improves when the distances from the relays to the eavesdropper are larger than the distances from the relays to the destination, and the cognitive network is far enough from the primary user.

A Study of the Improvement and Practical Use on the Website Measurement Scale (웹사이트 측정도구의 개발과 활용에 대한 연구)

  • Kim, Dae-Hwan;Bae, Young
    • Survey Research
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    • v.10 no.1
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    • pp.91-112
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    • 2009
  • The aim of this study is to suggest a new website measurement scale revised in accordance with the present tendency, and to test the practical use of it. The empirically current studies suggest the information, connectivity, practical function, lay - out, design, interlace, system, service as a website measurement scale. However. this study suggest a new website measurement scale including communication between internet users, platform for editing information. The test of a practical use about measurement scale progressed by a survey on computer access. A sample of 300 internet users answered the question based on a new website measurement scale. The result of this study shows that primary factors of the website measurement scale are information, user interface, website service, and communication. The influence of these factors on user's website preference changed as compared with the past. The result also shows that there is close correlation between information factor and communication factor. And the communication factor suggested on this study has effected in user's website satisfaction. Results imply that the idea of web2.0 is practically an important strategy for improving website satisfaction. And, because influence of primary factors on the website satisfaction has changed continually, strategic planning will have to be kept up.

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Efficient Spectrum Sensing for Cognitive Radio Sensor Networks via Optimization of Sensing Time (센싱 시간의 최적화를 통해 인지 무선 센서 네트워크를 위한 효율적인 스펙트럼 센싱)

  • Kong, Fanhua;Cho, Jinsung
    • Journal of KIISE
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    • v.43 no.12
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    • pp.1412-1419
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    • 2016
  • In cognitive radio sensor networks (CRSNs), secondary users (SUs) can occupy licensed bands opportunistically without causing interferences to primary users (PUs). SUs perform spectrum sensing to detect the presence of PUs. Sensing time is a critical parameter for spectrum sensing that can yield a tradeoff between sensing performance and secondary throughput. In this study, we investigate new approaches for spectrum sensing by exploring the tradeoff from a) spectrum sensing for PU detection (SSPD) and b) spectrum sensing for secondary throughput (SSST). In the proposed scheme, the first sensing result of the current frame determines the dynamic performance of the second spectrum sensing. Energy constraint in CRSNs leads to maximized network energy efficiency via optimization of sensing time. Simulation results show that the proposed scheme of SSPD and SSST improves network performance in terms of energy efficiency and secondary throughput, respectively.

An Improved DSA Strategy based on Triple-States Reward Function (Triple-state 보상 함수를 기반으로 한 개선된 DSA 기법)

  • Ahmed, Tasmia;Gu, Jun-Rong;Jang, Sung-Jeen;Kim, Jae-Moung
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.11
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    • pp.59-68
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    • 2010
  • In this paper, we present a new method to complete Dynamic Spectrum Access by modifying the reward function. Partially Observable Markov Decision Process (POMDP) is an eligible algorithm to predict the upcoming spectrum opportunity. In POMDP, Reward function is the last portion and very important for prediction. However, the Reward function has only two states (Busy and Idle). When collision happens in the channel, reward function indicates busy state which is responsible for the throughput decreasing of secondary user. In this paper, we focus the difference between busy and collision state. We have proposed a new algorithm for reward function that indicates an additional state of collision which brings better communication opportunity for secondary users. Secondary users properly utilize opportunities to access Primary User channels for efficient data transmission with the help of the new reward function. We have derived mathematical belief vector of the new algorithm as well. Simulation results have corroborated the superior performance of improved reward function. The new algorithm has increased the throughput for secondary user in cognitive radio network.

Applications of haptic feedbacks in medicine (의료분야에서의 햅틱 피드백 응용)

  • Quy, Pham Sy;Seo, An-Na;Kim, Hyung-Seok;Kim, Jee-In
    • 한국HCI학회:학술대회논문집
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    • 2009.02a
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    • pp.203-213
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    • 2009
  • Medicine is one of great application fields where Virtual Reality (VR) technologies have been successfully utilized. The VR technologies in medicine bring together an interdisciplinary community of computer scientists and engineers, physicians and surgeon, medical educator and students, military medical specialists, and biomedical futurists. The primary feedback of a VR system has been visual feedback. The complex geometry for graphic objects and utilizing hardware acceleration can be incorporated with in order to produce realistic virtual environments. To enhance human-computer interaction (HCI), in term of immersive experiences perceived by users, haptic, speech, olfactory and other non-traditional interfaces should also be exploited. Among those, hapic feedback has been tightly coupled with visual feedback. The combination of the two sensory feedbacks can give users more immersive, realistic and perceptive VR environments. Haptic feedback has been studied over decades and many haptic based VR systems have been developed. This paper focuses on haptic feedback in term of its medical usages. It presents a survey of haptic feedback techniques with their applications in medicine.

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