• 제어로봇시스템학회논문지
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• 제14권2호
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• pp.184-190
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• 2008

This paper describes a message model based on XML (eXtensible Markup Language) to present real-time data from sensors and instruments at manufacturing processes for web service. HTML (Hyper Text Markup Language) is inadequate for describing real-time data from process control plants while it is suitable for displaying non-real-time multimedia data on web. For XML-based web service of process data, XML format for the data presentation was proposed after investigating data of various instruments at steel-making plants. Considering transmission delay inevitably caused from increased message length and processing delay from transformation of raw data into defined format, which was critical for operation of a real-time system, its performance was evaluated by simulation. In the simulation, we assumed two implementation models for conducting the transformation function. In one model, transformation was done at an SCC (Supervisory Control Computer) after receiving real-time data from instruments. In the other model, transformation had been carried out at instruments before the data were transmitted to the SCC. Various tests had been conducted under different conditions of offered loads and data lengths and their results were described.

• Journal of information and communication convergence engineering
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• 제10권3호
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• pp.231-236
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• 2012

For real-time wireless sensor network applications, it is essential to provide different levels of quality of service (QoS) such as reliability, low latency, and fault-tolerant traffic control. To meet these requirements, an (m,k)-firm based real-time routing protocol has been proposed in our prior work, including a novel local transmission status indicator called local DBP (L_DBP). In this paper, a fault recovery scheme for (m,k)-firm real-time streams is proposed to improve the performance of our prior work, by contributing a delay-aware forwarding candidates selection algorithm for providing restricted redundancy of packets on multipath with bounded delay in case of transmission failure. Each node can utilize the evaluated stream DBP (G_DBP) and L_DBP values as well as the deadline information of packets to dynamically define the forwarding candidate set. Simulation results show that for real-time service, it is possible to achieve both reliability and timeliness in the fault recovery process, which consequently avoids dynamic failure and guarantees meeting the end-to-end QoS requirement.

• 한국멀티미디어학회논문지
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• 제20권5호
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• pp.808-826
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• 2017

Most of conventional DSS's(Digital Signage Systems) have been built based on LAMP framework. Recent researches have shown that MEAN or MERN stack framework is simpler, more flexible, faster and more suitable for web-based application than LAMP stack framework. In this paper, we propose a design and implementation of MEARN (ME(A+R)N) stack-based real-time digital signage system, MR-DSS, which supports handing real-time tasks like urgent/instant messaging, system status monitoring and so on, efficiently in addition to conventional digital signage CMS service tasks. MR-DSCMS, CMS of MR-DSS, is designed to provide most of its normal services by REST APIs and real-time services like urgent/instant messaging by Socket.IO base under MEARN stack environment. In addition to architecture description of components composing MR-DSS, design and implementation issues are clarified in more detail. Through experimental testing, it is shown that 1) MR-DSS works functionally well, 2) the networking load performance of MR-DSCMS's REST APIs is better compared to a well-known open source Xibo CMS, and 3) real-time messaging via Socket.IO works much faster than REST APIs.

• 디지털융복합연구
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• 제16권12호
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• pp.335-342
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• 2018

포털 사이트의 핵심 서비스인 검색서비스는 입력되는 검색어 중에서 짧은 순간에 급상승하는 검색어를 대상으로 순간 검색빈도가 높은 것을 기준으로 순위별로 제시하는 것이므로 일정기간 동안 관심도가 높은 검색어를 곧바로 알려주기는 힘들다. 따라서 이를 극복하고 검색어 변화에 대한 향상된 분석결과가 나오게 하여 보다 지능적인 정보검색 서비스를 제공하기 위한 노력이 필요하다. 이를 위하여 본 논문에서는 실시간검색어의 관심도와 지속도, 그리고 주목도를 측정할 수 있는 기준을 제시한다. 그리고 그 기준에 맞추어 일정기간 동안 시간, 일간, 주간, 월간 실시간검색어에 대한 변화의 측정과 집계를 하고 이를 통해 관심도가 높은 이슈, 관심이 길게 지속된 이슈, 변화가능성이 커서 앞으로 주목해야 할 이슈를 평가한다.

• 대한의용생체공학회:의공학회지
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• 제22권4호
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• pp.377-383
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• 2001

In this paper, we present an intensive patient monitoring service through the Internet, which enables medical doctors to watch their patients in a remote site, to monitor their vital signs and to give them some advices for first-aid treatment. The service consists of three service objects: Monitoring Information Service(MIS), Vital Sign Monitoring Service(VSMS) and Multimedia Consulting (MCS). Through the MIS, medical doctors can get information about the patients currently under monitoring, including their names, ages, genders, symptoms, current main complaints and current locations. The VSMS enables medical doctors to monitor in real-time patients' vital signs such as electrocardiogram (ECG), respiration, temperature, blood oxygen saturation (SpO$_{2}$), invasive blood pressure (IBP), and non-invasive blood pressure (NIBP). It also generates alarms when the patients are likely to be in a critical situation. The MCS provides a real-time multimedia desktop conferencing facility for watching patients and instructing attendants to administer some first-aid treatment. We carried out some experiments according to two different scenarios. The intensive patient monitoring service was functioning well in a 100Base-T Ethernet LAN environment.

• International Journal of Internet, Broadcasting and Communication
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• 제10권3호
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• pp.26-34
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• 2018

In this paper, we propose a scheduling scheme that can efficiently serve I/O requests having deadlines in flash storage. The I/O requests with deadlines, namely, real-time requests, are assumed to be issued for streaming services of continuous media. Since a Web-based streaming server commonly supports downloads of HTMLs or images, we also aim to quickly process non-real-time I/O requests, together with real-time ones. For this purpose, we adopt the well-known rate-reservation EDF (RR-EDF) algorithm for determining scheduling priorities among mixed I/O requests. In fact, for the use of an EDF-style algorithm, overhead of task's switching should be low and predictable, as with its application of CPU scheduling. In other words, the EDF algorithm is inherently unsuitable for scheduling I/O requests in HDD storage because of highly varying latency times of HDD. Unlike HDD, time for reading a block in flash storage is almost uniform with respect to its physical location. This is because flash storage has no mechanical component, differently from HDD. By capitalizing on this uniform block read time, we compute bandwidth utilization rates of real-time requests from streams. Then, the RR-EDF algorithm is applied for determining how much storage bandwidth can be assigned to non-real-time requests, while meeting deadlines of real-time requests. From this, we can improve the service times of non-real-time requests, which are issued for downloads of static files. Because the proposed scheme can expand flexibly the scheduling periods of streams, it can provide a full usage of slack times, thereby improving the overall throughput of flash storage significantly.

• 서비스연구
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• 제10권3호
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• pp.55-66
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• 2020

본 연구는 2020년초 조성된 코로나바이러스 위기에서 실시된, 비대면 실시간 영상강의 서비스에 대한 평가와 성과를 실증하기 위해 시도되었다. 강의서비스를 서비스시스템 관점에서 서비스생산과 서비스전달로 구분하여 그 역할과 수준을 평가하며, 학습자들이 인지하는 강의 서비스편익과 서비스만족도와의 관계를 실증하였다. 이러한 구조적 영향 관계를 실증하기 위해서 G대학교 학부 총268명을 대상으로 설문을 통해 분석한 결과, 비대면 실시간 영상 강의서비스시스템의 역할 및 수준은 학습자들의 서비스편익 및 서비스만족도에 영향을 미치며 서비스편익 또한 서비스만족도에 영향을 미치는 것으로 나타났다. 추가분석에서는 학습지향성이 높은 그룹에서는 관계지향성이 높은 그룹과 비교하여 강의서비스에서 서비스시스템 수준이나 역할 그리고 그로부터 인식하는 서비스 편익 자체를 더 높게 인식하고 있다. 그리고 과거에 대면수업이 이루어졌을 때 등교하여 비교과활동이 많은 학습자그룹에서는 그렇지 않은 학습자그룹에서보다 코로나바이러스 방역이라는 편익을 더 낮게 인식하고 있다. 이로써 관계지향성이 높은 그룹에 대한 강의서비스에서의 역할기대를 파악하여 서비스를 보완할 필요가 있고, 비교과활동을 선호하는 그룹에 대한 보완책도 필요하다.

• 한국컴퓨터정보학회논문지
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• 제21권5호
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• pp.57-64
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• 2016

In this paper, we propose the design of railway safety common data model to provide common transformation method for collecting data from railway facility fields to Real-time railway safety monitoring and control system. This common data model is divided into five abstract sub-models according to the characteristics of data such as 'StateInfoMessage', 'ControlMessage', 'RequestMessage', 'ResponseMessage' and 'ExtendedXXXMessage'. This kind of model structure allows diverse heterogeneous data acquisitions and its common conversion method to DDS (Data Distribution Service) format to share data to the sub-systems of Real-time railway safety monitoring and control system. This paper contains the design of common data model and its DDS Topic expression for DDS communication, and presents two kinds of data transformation case studied for verification of the model design.

• 한국동물위생학회지
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• 제31권4호
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• pp.485-492
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• 2008

Salmonella enterica serovars Gallinarum(SG, causative agent of fowl typhoid) and S Pullorum(SP, causative agent of pullorum disease) are very important bacterial pathogens in poultry industry. They share some common antigenic properties though the characteristics of outbreaks are quite different. To discriminate between SG and SP, we developed two rapid diagnostic methods, allele-specific real-time PCR and 3'-tailed PCR over 2 single nucleotide polymorphisms ($237^{th}\;and\;598^{th}$). In both methods, $237^{th}$ allele was found to be a good target for differential diagnosis, while $598^{th}$ allele produced some non-specific reactions.

• 한국융합학회논문지
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• 제1권1호
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• pp.17-21
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• 2010

본 논문에서는 실시간 웹 서비스 시스템에서 과부하를 조절하는 기법을 제안한다. 기존의 많은 기법은 단순히 웹 연결 수를 조절하여 과부하를 방지한다. 이는 웹서버의 요청 처리를 위한 추가적인 웹 태스크의 생성을 조절하는 것만 가능하고, 이미 생성된 웹 태스크나 내부 디바이스의 최신 상태를 알려주기 위해서 주기적 동작하는 내부의 실시간 태스크 등에 대해서는 과부하 방지를 위한 아무런 조치를 취하고 있지 않다. 본 논문에서는 주기적 동작하는 내부의 실시간 태스크 등에 대해서도 동적으로 부하를 반영할 수 있는 제어기를 설계한다. 설계된 제어기를 적용한 피드백제어 시스템을 구성하여 안정된 부하 조절이 가능함을 확인하였다.