• 한국컴퓨터정보학회논문지
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• 제24권1호
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• pp.121-128
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• 2019

An Internet of Things(IoT) technology which provides intelligent services by combining context-awareness based intelligences, inter-communication is made of between things and things or between things and person through the network connected with intelligent things is spreading rapidly. Especially as this technology is converged into smart device, mobile, cloud, big data technologies, it is applied into various domains. Therefore, this is different from existing Web or Mobile Application. New types of IoT applications are emerging by adapting IoT into Web or mobile. Because IoT application is not only focused on software but also considering hardware or things aspect, there are limitations existing development process. Existing development processes don't consider analysis and design techniques considering both hardware and things. We propose not only a meta-model for development process which can support IoT application's development but also meta-models for main activities in this paper. Especially we define modeling elements by using UML's extension mechanisms, provide development process, and suggest design techniques how to apply those elements into IoT application's modeling phase. Because there are many types of IoT application's type, we propose an Android and Arduino-based on IoT application as a case study. We expect that proposed technique can be applied into many of various IoT application development and design with a form of flexible and extensible as well as main functionalities or elements are more concretely described. As a result, it brings IoT application's flexibility and the effect of quality improvement.

• 융합신호처리학회논문지
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• 제24권2호
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• pp.112-118
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• 2023

IoT 기술은 인터넷과 사물이 연결되고, 사물 스스로가 데이터를 분석, 판단하여 실세계와 가상세계를 실시간으로 상호 연결하는 단계로 발전하고 있다. 이러한 IoT 기술은 센서, 액추에이터, 장치, 네트워크로 구성되어 다양한 분야에 적용되고 있으며, IoT 디바이스와 애플리케이션 수가 증가함에 따라 데이터 트래픽도 증가하고 있다. 본 논문에서는 IoT 환경에서의 IoT 디바이스와 브로커 간 성능 분석을 위해 IoT 디바이스에서 센서 데이터를 수집하고 MQTT 프로토콜을 통해 MQTT 브로커에 전달하는 시스템을 구현하였다. MQTT 기반 RTT 측정과 IoT 디바이스와 브로커 간 메시지 전송 시간을 측정하는 실험을 수행한 결과 패킷 손실은 발생하지 않았으며, 전파 지연이 RTT에 영향을 주는 것으로 실험을 통해 알 수 있었다.

• Tuberculosis and Respiratory Diseases
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• 제40권4호
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• pp.357-366
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• 1993

연구배경 : $^{99m}Tc$-DTPA의 폐청소율은 폐포상피세포의 손상도를 반영하고 일부 질환에서는 기존의 폐기능검사보다 더 예민한 것으로 알려져 있다. 흡입된 $^{99m}Tc$-DTPA의 폐청소율은 $^{99m}Tc$-DTPA가 침착되는 부위에 의해 많은 영향을 받아 체외에서 감마카메라로 폐의 방사능 소실속도를 측정하는 방법으로는 섬모운동에 의한 청소속도와 폐포상피를 통한 흡수속도를 구분 할 수 없어 전체 폐의 방사능 소실속도가 폐포상피세포의 투과성만을 반영한다고 할 수 없고 또 장시간동안 감마카메라로 촬영을 해야하는 등 방법이 복잡하다. 흡입된 $^{99m}Tc$-DTPA는 체내에서 24시간 이내에 모두 소변으로 배설되고, 첫 2시간동안 소변으로 배설되는 $^{99m}Tc$-DTPA량은 폐포상피세포를 통한 흡수속도에 의해 결정된다고 알려져 있어, 본 연구자들은 2시간과 24시간 소변내의 방사능배설량의 비를 이용하여 간편하게 폐청소율을 구하는 방법의 유용성 여부를 관찰하기 위해 본 연구를 시행하였다. 방법 : 비흡연 정상인과 미만성 간질성 폐질환환자들을 대상으로 폐기능 검사를 시행하였고 $^{99m}Tc$-DTPA를 vaporizer를 통하여 5분간 흡입후 앙와위에서 폐의 후부상을 감마카메라로 1분단위영상방식으로 30분간 컴퓨터에 수록하여 폐방사능 반감기($T_{1/2}$)를 구하였으며, 또 흡입후 2시간과 24시간 소변을 모아 2시간대 24시간 소변내 방사능배설량비를 구하여 다음과 같은 결과를 얻었다. 결과: 1) 비흡연 정상인에서 $T_{1/2}$와 2시간대 24시간 소변내 방사능배설량비간에는 통계적으로 의미있는 역상관관계가 관찰되었다(r=-0.77, p<0.05). 미만성 폐질환 환자에서 폐방사능 반감기와 2시간대 24시간 소변내 방사능배설량비간에도 역시 의미있는 역상관관계가 관찰되었다 (r=-0.63, p<0.05). 2) 미만성 간질성 폐질환 환자에서 $T_{1/2}$는 $38.65{\pm}11.63$분으로 비흡연 정상인의 $55.53{\pm}11.15$분에 비하여 통계적으로 유의하게 짧았으며, 2시간대 24시간 소변내 방사능배설량비 역시 미만성 간질성 폐질환 환자에서 $52.15{\pm}10.07%$로 비흡연 정상인의 $40.43{\pm}5.53%$에 비해 유의하게 증가되어 있었다(p<0.05). 3) $T_{1/2}$나 2시간대 24시간 소변내 방사능배설량비는 환자군에서 폐확산능과 유의한 상관관계가 없었다(p>0.05). 결론 : 이상의 결과로 $^{99m}Tc$-DTPA의 2시간대 24시간 소변내 방사능배설량비는 폐포상피세포의 투과성을 잘 반영하여 폐포상피세포의 손상정도를 반영하는 간편한 bedside 검사로 생각되며 특히, 폐포상피세포 투과성이 증가되어 있는 미만성 간질성 폐질환 환자에서 예민한 추적경사로 폐확산능과 상호보완적으호 유용하게 사용될 수 있을 것으로 생각된다.

• 대한기계학회논문집A
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• 제24권5호
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• pp.1331-1342
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• 2000

In power generation systems a variety of structural components typically operate at high temperature and pressure. Therefore a life assessment methodology accounting for gradual creep fracture is increasingly needed for these components. The most critical defects in such structure are generally found in the form of semi-elliptical surface cracks in the welded tubular joints. Therefore the analysis of a semi-elliptical surface crack in a plate or a shell is an important problem in engineering fracture mechanics. On this background, via shell/line-spring finite element analyses of such surface cracks in the welded T and L joints under various loadings, we investigate J-integral along the crack front We first develop T and L joints auto mesh generation program providing ABAQUS input file composed of shell/line-spring finite elements. We then further develop a T and L joints life assessment program based on the experimental creep crack growth law and auto mesh generation program in a graphical user interface format Finally the remaining life of T and L joints for various analytical parameters are assessed using the developed life assessment program.

• Steel and Composite Structures
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• 제24권5호
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• pp.615-633
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• 2017

Fatigue crack initiated in welded tubular joints due to cyclic loading may produce harmful effect on the integrity of the tubular structures. To study such effect, both fatigue and static tests on nine circular tubular T-joint specimens made of carbon steel materials were carried out. The specimens were subjected to tensile loading in both fatigue and static tests. The load-displacement relation, the crack propagation and the failure mode of the specimens are all analyzed. The deterioration of the static strength of the cracked T-joints is also investigated and evaluated through an area reduction factor. Experimental results indicate that the static strength of a tubular T-joint with a surface crack seems to decrease slightly while a through crack has relatively remarkable effect on the reduction of the static strength. Additionally, experimental results also show that the toughness of the materials and the geometry of the specimens play an important role on the failure process of cracked tubular T-joints.

• 성인간호학회지
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• 제24권1호
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• pp.20-30
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• 2012

Purpose: This study was to explore the gap between awareness and performance toward evidence-based pain management in older adults for the purpose of establishing baseline data for evidence-based pain management protocol development and dissemination. Methods: The subjects were 290 staff nurses from three general hospitals. Self administered questionnaires were used to collect the data and the results of the study were analyzed with descriptive statistics, t-test, ANOVA and Pearson's correlation. Results: There were statistically significant differences between awareness and performance in pain assessment (t=17.31, $p$ <.001), patient and family education (t=17.33, $p$ <.001), pharmacologic management (t=12.99, $p$ <.001), non pharmacological management (t=16.28, p<.001), and evaluation of effectiveness (t=11.70, $p$ <.001). There were also statistically significant differences in awareness and performance according to the workplace, knowledge, and usual performance. Conclusion: The study showed that the hospital nurses' performance about evidence-based pain management in older adults was lower than their awareness level thus indicating significant gaps between evidence and actual practice. To ensure effective pain care, the factors contributing to these gaps need to be analyzed to identify the barriers. In addition, the evidence-based pain management guideline suitable for various clinical settings needs to be developed and disseminated.

• 수산해양교육연구
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• 제24권2호
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• pp.234-245
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• 2012

This study aims to analyze the factors of the extra-curricula area in personal school performance record and propose the practical strategies for entrance examination affairs on this area. To address this goal, we have applied a SWOT analysis with related documents and research results. We found out five strengths: (S1) Link the students' experience to right people for the university, (S2) Quantitative Indicators, (S3) Qualitative Indicators, (S4) Link to other evaluation factors, and (S5) Analysis of Human Resource. The weakness included: (W1) Fairness, (W2) Reliability, (W3) Difficulties to set standards, (W4) Difficulties to set environments, and (W5) Lack of systemic experience of an evaluation. We also discovered five opportunities (O1) Recognition of public education, (O2) The need of national support, (O3) The importance of autonomy, (O4) Specialization, and (O5) Networks. Finally, threat factors consisted of: (T1) Frequent change of educational policy, (T2) Increasing of private education, (T3) Lack of information and preparation time, and (T4) The accuracy and reliability of personal school records. Based on these results, we suggested practical strategies with these four dimensions: S-O, W-O, S-T, and W-T.

• 한국멀티미디어학회논문지
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• 제24권8호
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• pp.1101-1113
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• 2021

The rapid growth of sense-and-respond applications and the emerging cloud computing model present a new challenge: providing publish/subscribe middleware as a scalable and elastic cloud service. The publish/subscribe interaction model is a promising solution for scalable data dissemination over wide-area networks. In addition, there have been some work on the publish/subscribe messaging paradigm that guarantees reliability and availability in the face of node and link failures. These publish/subscribe systems are commonly used in information-centric networks and edge-fog-cloud infrastructures for IoT. The IoT has an edge-fog cloud infrastructure to efficiently process massive amounts of sensing data collected from the surrounding environment. In this paper. we propose a quorum-based hierarchical fault-tolerant publish/subscribe systems (QHFPS) to enable reliable delivery of messages in the presence of link and node failures. The QHFPS efficiently distributes IoT messages to the publish/subscribe brokers in fog overlay layers on the basis of proposing extended stepped grid (xS-grid) quorum for providing tolerance when faced with node failures and network partitions. We evaluate the performance of QHFPS in three aspects: number of transmitted Pub/Sub messages, average subscription delay, and subscritpion delivery rate with an analytical model.

• International Journal of Computer Science & Network Security
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• 제24권6호
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• pp.99-108
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• 2024

The Internet of Things (IoT) is a novel concept that allows a large number of objects to be connected to the Internet while also allowing them to be controlled remotely. The Internet of Things is extensive and has become an almost inseparable part of our daily lives. Users' personal data is frequently obtained by these linked gadgets and stored online. In recent years, the security of acquired data has become a major concern. As devices grow more linked, privacy and security concerns grow more pressing, and they must be addressed as soon as possible. IoT implementations and devices are particularly vulnerable to attacks that might adversely affect customer security and privacy, which might have an impact on their practical utility. The goal of this study is to bring attention to the security and privacy concerns that exist in IoT systems. To that purpose, the paper examines security challenges at each level of the IoT protocol stack, identifies underlying impediments and critical security requirements, and provides a rapid overview of available security solutions for securing IoT in a layered environment.

• 근관절건강학회지
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• 제24권2호
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• pp.77-88
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• 2017

Purpose: The purpose of this study was to examine the effects of cardiocerebrovascular disease prevention program for older adults who were members of a elderly school located in Y city on knowledge of cardiocerebrovascular disease, depression, and physiological parameters. Methods: Nonequivalent control group pretest-posttest design was employed. A total of 50 older people living in Y city were assigned into an experimental group (n=26) or a control group (n=24). The experimental group participated in a 8-weeks cardiocerebrovascular disease prevention program from October 10 to December 2 in 2016. Data were analyzed with SPSS/WIN 21.0 using descriptive statistics, $x^2$ test, Fisher's exact test, and t-test. Results: The results indicated significant differences between the experimental group and control group in the scores of knowledge of cardiocerebrovascular disease (t=-4.60, p<.001), depression(t=3.65, p=.001), physiological parameters including systolic blood pressure (t=6.58, p<.001), diastolic blood pressure (t=4.56, p<.001), and blood glucose level (t=3.04, p=.004). Conclusion: The cardiocerebrovascular disease prevention program have a significant effect on the change of knowledge of cardiocerebrovascular disease, depression, and physiological parameters for elderly school participants.