• 대기
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• 제20권2호
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• pp.153-160
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• 2010

In this paper, an attempt has been made to build and test self-configuring weather sensor networks and internet based observation system to gather atmospheric data. The aim is to provide integrated or real-time weather information in standard form using network data access protocol. This system was successfully developed to record weather information both digital as well as visual using sensor network and web-enabled surveillance cameras. These data were transformed by network based data access protocol to access and utilize for public domain. The competed system has been successfully utilized to monitor different types of weather. The results show that this is one of the most useful weather monitoring system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.595-600
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• 2011

This study analyzed passenger's access modes that connect to regional railway station and developed a model of access mode choice based on transit smart card data of Seoul station as a case study. The study boundary includes sixteen bus stops around the station. The results show that most passengers access to station have less than two transfers. Of total 15000, eighty percent of passengers use metro and the rest of people take a bus. Interestingly, it is found that almost same proportions of passengers use metro and bus for egress the station. Consequently, metro is found to be most likely used mode compared to bus for both access and egress trips.

• Journal of Contemporary Eastern Asia
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• 제19권1호
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• pp.1-7
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• 2020

The ongoing COVID-19 pandemic once again demonstrated how crucial it is to have unlimited access to scientific information. At the same time, the economic disparities that the pandemic revealed and aggravated made us realize that many of us cannot afford access to expert knowledge. While the international community is speculating about possible outcomes of the crisis, one can be said for sure, the pandemic accelerated many inevitable changes that would otherwise happen at a slower pace including increasing digitalization of the society and the expanding role of open data in the life of the academic community.

• 전자공학회논문지A
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• 제31A권7호
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• pp.1-16
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• 1994

In this paper, we propose a new multiple access scheme for VSAT(Very Small Aperture Terminal) data communications. The proposed scheme has better performance in terms of delay throughput than Controlled Multiaccess Scheme which has excellent performance. The proposed scheme use the spare reservation method, adaptation method to offered load, and fixed bandwidth reservation method. In this paper, we analyze the performance using simple queueing model and present the simulation results. When network traffic is very low, the new scheme and the controlled multiaccess scheme have almost the same access delay characteristic. As the network load becomes higher, the new scheme's access delay gain becomes larger. Futhermore, even when the network traffic is very high it is possible to access satellite link within the delay similar to one round-trip delay. In addition to access delay performance enhancement, the new scheme has facility that supports fixed bandwidth reservation. So it shows more enhanced performance in the environment that stream traffic is dominant such as in VSAT communication environment.

• 기술혁신학회지
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• 제8권3호
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• pp.1060-1086
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• 2005

In this paper, we attempt to predict the future of broadband access market where new convergence access technologies and additional services are introduced, based on consumer preferences. Conjoint analysis and mixed logit model is used for estimation, From the results, consumers value convergence access technologies such as PLC and wireless LAN, and TV-related service, However, valuation on new beneficial features of convergence access technologies is not enough to overcome their technological inferiorities in data transfer speed and quality stability at current technological stage, Additionally, consumer preferences are so heterogeneous that differentiated business strategies are required, Finally, some managerial and policy implications are presented.

• International Journal of Advanced Culture Technology
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• 제11권2호
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• pp.315-322
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• 2023

Intelligent IoT environments that accommodate a very large number of clients require technologies that provide secure information service regardless of the number of clients. Wireless data broadcast is an information service technique that ensures scalability to deliver data to all clients simultaneously regardless of the number of clients. In wireless data broadcasting, clients access the wireless channel linearly to explore the data, so the access time of clients is greatly affected by the broadcast cycle. Data compression-based data broadcasting can reduce the broadcast cycle and thus reduce client access time. Therefore, a simulation framework that can evaluate the performance of data broadcasting by applying different data compression algorithms is essential and important. In this paper, we propose a simulation framework to evaluate the performance of data broadcasting that can adopt data compression. We design the framework that enables to apply different data compression algorithms according to the data characteristics. In addition to evaluating the performance according to the data, the proposed framework can also evaluate the performance according to the data scheduling technique and the kind of queries the client wants to process. We implement the proposed framework and evaluate the performance of data broadcasting using the framework applying data compression algorithms to demonstrate the performances of data compression broadcasting.

• 인터넷정보학회논문지
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• 제17권5호
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• pp.9-16
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• 2016

Pervasive computing and Internet of Things (IoT) have recently received considerable interest to deploy solutions for the future Internet. Smart environments are integrated with Semantic Web to provide context-awareness to the processed information. Self-learning techniques have been adopted within smart solutions for efficient retrieval of data but do not process data with privacy parameters for in-place authorization. To overcome this issue, we present a novel approach of deploying access control as a service mechanism within Semantic Web based smart environment by using eXtensible Access Control Markup Language (XACML). The proposed XACML as a Service (XACMLaaS) approach offers fine-grained access control for protecting information within smart environment. In this paper, we have defined mathematical rules for each components of proposed access control service layer. These rules are for implementation of access control using XACML. The proposed approach allows the adaptation of authorization of information at component level and provides scalable solution for authorization policies and rule enforcement within smart environment.

• Journal of Communications and Networks
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• 제2권1호
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• pp.46-57
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• 2000

Ongoing standardization effort on 3G cellular system in 3GPP (UNTS) is based on GPRS core network and promises a global standard for systems capable of offering ubiquitous access to internet for mobile users. Considered radio access systems(FDD CDMA, TDD CDMA, and EDGE) are optimized for robust mobile use. However, there are alternative relatively high-rate radio interfaces being standardized for WLAN (IEEE802.11 and HIPER-LAN/2) which are capable of delivering significantly higher data rates to static or semi-static terminals with much less overhead. Also WPANs(BLUETOOTH, IEEE802.15), which will be present in virtually every mobile handset in the near future, are offering low cast and considerable access data rate and thus are very attractive for interworking scenarios. The prospect of using these interfaces as alternative RANs inthe modular UMTS architecture is very promising. Additionally, the recent inclusion of M-IP in the UMTS R99 standard opens the way for IP-level interfacing to the core network. This article offers an overview into WLAN-Cellular interworking. A brief overview of GPRS, UMTS cellular architectures and relevant WLAN standards is given. Possible interworking architectures are presented.

• 디지털산업정보학회논문지
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• 제12권1호
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• pp.35-41
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• 2016

Internet of Things (IoT) services are widely used in appliances of daily life and industries. IoT services also provide various conveniences to users and are expected to affect value added of all industries and national competitiveness. However, a variety of security threats are increased in IoT environments and lowers reliability of IoT devices and services that make some obstacles for commercialization. The attacks arising in IoT environments are making industrial and normal life accidents unlike existing information leak and monetary damages, and can expand damage scale of leakage of personal information and privacy more than existing them. To solve these problems, we design a session key based access control scheme for secure communications in IoT environments. The proposed scheme reinforces message security by generating session key between device and access control network system. We analyzed the stability of the proposed access scheme in terms of data forgery and corruption, unauthorized access, information disclosure, privacy violations, and denial of service attacks. And we also evaluated the proposed scheme in terms of permission settings, privacy indemnity, data confidentiality and integrity, authentication, and access control.

• 한국컴퓨터정보학회논문지
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• 제24권7호
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• pp.45-52
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• 2019

With the popularity of mobile Internet and smart phones, the domestic digital music access platform has entered a period of rapid development. Existing studies in the academic circle have shown that experience has a positive impact on user perception and loyalty. However, the research on the relationship between brand loyalty, user perception and user experience of Internet products has not received much attention. Starting from the brand loyalty theory and user experience theory, this paper explores the mechanism of user experience, user perception and brand loyalty of digital music access platform. Based on the development status of digital music access platform in China, the purpose is to explore how the user experience of the mainstream digital music access platform can affect Usefulness Perception, Epidemic Perception. And to explore how the Usefulness Perception, Epidemic Perception can affect users' brand loyalty. also further explore the role of users' perception in this process to understand the relationship between brand and user experience. In practical operations, 398 formal questionnaires were issued online to collect first-hand data, and reliability analysis, factor analysis, correlation analysis and hypothesis analysis were carried out successively on the data in the later stage. Through research, it is found that the user experience of digital music access platform has a partial significant impact on the perception and loyalty of applications. The visual presentation and emotional feelings of digital music access platform are positively correlated with the perceived usefulness of applications. The visual presentation and emotional feelings of digital music access platform are positively correlated with the perceived popularity of applications. The e perceived usefulness and perceived popularity of the digital music access platform are positively correlated with the loyalty of the application. Through this research, it has certain guiding significance to the promotion of digital music access platform's brand loyalty degree.