• Journal of KIISE
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• v.44 no.2
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• pp.213-222
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• 2017

The Internet of Things (IoT) technology is rapidly developing in recent years, and is applicable to various fields. A smart factory is one wherein all the components are organically connected to each other via a WSN, using an intelligent operating system and the IoT. A smart factory technology is used for flexible process automation and custom manufacturing, and hence needs adaptive network management for frequent network fluctuations. Moreover, ensuring the timeliness of the data collected through sensor nodes is crucial. In order to ensure network timeliness, the power consumption for information exchange increases. In this paper, we propose an IEEE 802.15.4e DSME-based distributed scheduling algorithm for mobility support, and we evaluate various performance metrics. The proposed algorithm adaptively assigns communication slots by analyzing the network traffic of each node, and improves the network reliability and timeliness. The experimental results indicate that the throughput of the DSME MAC protocol is better than the IEEE 802.15.4e TSCH and the legacy slotted CSMA/CA in large networks with more than 30 nodes. Also, the proposed algorithm improves the throughput by 15%, higher than other MACs including the original DSME. Experimentally, we confirm that the algorithm reduces power consumption by improving the availability of communication slots. The proposed algorithm improves the power consumption by 40%, higher than other MACs.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.6
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• pp.782-792
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• 1999

효과적인 ATM 망의 관리는 연결 지향 환경, 다양한 서비스 등급, 대규모 트래픽, 가상 망 구성 그리고 여러가지 트래픽 유형 등과 같은 다양한 ATM 특성을 다룰 수 있어야만 한다. 이를 위해 ATM 포럼에서는 ATM 장치, 사설망, 공중망 및 그들간의 상호작용을 지원하기 위한 ATM 망 관리 참조 모델을 정의하였으며, 그 중 하나가 서로 다른 판매자로부터의 ATM 장비들간의 상호동작성을 보장하기 위해 SNMP 기반 망 관리 프로토콜을 통해 상호 연결된 인터페이스를 관리할 수 있도록 정의된 통합 지역 관리 인터페이스(ILMI) 프로토콜이다. ILMI의 목적은 두 인접한 ATM 장치로 하여금 그들 간에 공통의 ATM 링크에 대한 동작 파라메타를 자동적으로 구성할 수 있도록 함으로서, 관리자에 의해 수동 구성이 아닌 ATM 장치 상호간의 플러그 앤 플러그 기능을 지원하는데 있다. 본 논문에서는 이러한 ILMI 기술을 바탕으로 공중망 ATM 교환기에 연결된 가입자의 물리 인터페이스, ATM 계층 인터페이스, VPC 및 VCC의 구성 및 상태 정보를 효율적으로 관리하며, 가입자 시스템의 ATM 주소를 자동으로 등록, 관리할 수 있도록 하는 가입자 인터페이스 관리 시스템(SIMS)을 설계하고, 구현하였다. Abstract An effective ATM management must address the various features of ATM such as connection-oriented environment, varying class of service, large scale traffic, virtual network configurations and, and multiple traffic types. For this, ATM network management reference model defined by ATM Forum describes the various types of network management needed to support ATM devices, private networks, public networks, and the interaction between them. One of these types is Integrated Local Management Interface (ILMI) defined to manage interconnected interface through SNMP-based network management protocol for ensuring the interoperability of ATM devices from different vendors. The purpose of ILMI is to enable two adjacent ATM devices to automatically configure the operation parameters of the common ATM link between them and then to provide a Plug and Plug function to any ATM devices with not a passive configuration by manager but a automatic configuration. This paper design and implement a Subscriber Interface Management System (SIMS) which provide automatic registration and management of ATM address of subscriber system and efficiently manages physical interface of subscriber who is connected to public ATM switch, ATM layer interface, configuration information and status information of VPC and VCC.

• The KIPS Transactions:PartC
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• v.19C no.3
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• pp.191-208
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• 2012

Proxy Mobile IPv6 (PMIPv6) is designed to provide network-based mobility management support to an MN without any involvement of the MN in the mobility related signalling, hence, the proxy mobility entity performs all related signalling on behalf of the MN. The new principal functional entities of PMIPv6 are the local mobility anchor (LMA) and the mobile access gateway (MAG). In PMIPv6, all the data traffic sent from the MN gets routed to the LMA through a tunnel between the LMA and the MAG, but it still has the single point of failure (SPOF) and bottleneck state of traffic. To solve these problems, various approaches directed towards PMIPv6 performance improvements such as route optimization proposed. But these approaches add additional signalling to support MN's mobility, which incurs extra network overhead and still has difficult to apply to multiple-LMA networks. In this paper, we propose a improved route optimization in PMIPv6-based multiple-LMA networks. All LMA connected to the proxy internetworking gateway (PIG), which performs inter-domain distributed mobility control. And, each MAG keeps the information of all LMA in PMIPv6 domain, so it is possible to perform fast route optimization. Therefore, it supports route optimization without any additional signalling because the LMA receives the state information of route optimization from PIG.

• Journal of Broadcast Engineering
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• v.24 no.4
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• pp.592-601
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• 2019

For coronary procedures, X-ray angiogram images are useful for diagnosing and assisting procedures. It is challenging to accurately segment a coronary artery using only a single segmentation model in 2D X-ray images due to a complex structure of three-dimensional coronary artery, especially from phenomenon of vessels being broken in the middle or end of coronary artery. In order to solve these problems, the initial segmentation is performed using an existing single model, and the candidate regions for the sophisticate correction is estimated based on the initial segment, and the local patch-based correction is performed in the candidate regions. Through this research, not only the broken coronary arteries are re-connected, but also the distal part of coronary artery that is very thin is additionally correctly found. Further, the performance can be much improved by combining the proposed correction method with any existing coronary artery segmentation method. In this paper, the U-net, a fully convolutional network was chosen as a segmentation method and the proposed correction method was combined with U-net to demonstrate a significant improvement in performance through X-ray images from several patients.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.2 s.3
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• pp.43-54
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• 2003

As the demand for ubiquitous mobile wireless Internet grows, vehicles are receiving a lot of attention as new networking platforms. The demand for 4G all-IP networks encourages vehicle networks to be connected using IPv6. By means of network mobility (NEMO) support, we can connect sensors, controllers, local ,servers as well as passengers' devices of a vehicle to the Internet through a mobile router. The mobile router provides the connectivity to the Internet and mobility transparency for the rest of the mobile nodes of an in-vehicle nv6 network. So, it is .important for the mobile router to assure reliable connection and a sufficient data rate for the group of nodes behind it. To provide reliability, this paper proposes an adaptive multihoming architecture of multiple mobile routers. Proposed architecture makes use of different mobility characteristics of different vehicles. Simulation results with different configurations show that the proposed architecture increases session preservation thus increases reliability and reduces packet loss. We also show that the proposed architecture is adaptive to heterogeneous access environment which provide different access coverage areas and data rates. The result shows that our architecture achieves sufficient data rates as well as session preservation.

• Journal of the Korean Geophysical Society
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• v.3 no.4
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• pp.235-244
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• 2000

We studied basic ideas of a network based Gravity/Magnetic data processing server/client system which provides functions of data processing, forward modeling, inversion and data process on Data Base. This Java technology was used to provide facilities, socket communication and JDBC(Java Database Connectivity) technology to produce an effective and practical client application. The server computers are linked by network to process the MPI parallelized computing. This can provide useful devices of the geophysical process and modeling that usually require massive computing performance and time. Since this system can be accessed by lots of users, it can provides the consistent and confident results through the verified processing programs. This system also makes it possible to get results and outputs through internet when their local machines are connected to the network. It can help many users who want to omit the jobs of system administration and to process data during their field works.

• The Journal of Korean Society for School & Community Health Education
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• v.14 no.1
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• pp.61-70
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• 2013

Objectives: The purpose of this study analyzes the characteristics of safety education in schools, experience of accidents, and safety awareness level of elementary school students. It also presents realistic guidelines for safety education, which can effectively lead to the safety behavior of students. Methods: We carried out questionnaire survey by convenient sampling method to 6th grade students of 3 elementary schools in Gyeonggi-do area that can understand the questionnaire and express their own opinion for safety awareness from February 15, 2013 to February 1, 2013. We used a self-administered questionnaire and analyzed 266 questionnaires except dishonestly answered 34 questionnaires. Results: 1. For accident occurrence by gender, male students was higher than female students. Male students was also higher than female students among students having an accident(${\chi}^2$=5.142, p=0.029). There was statistical significance in accident occurrence by how they go to school. Students going to school on foot have higher accident rate(${\chi}^2$=11.447, p=0.010). 2. In terms of safety awareness level, students having no accident was higher than students having an accident(F=3.828, p=0.005) and students usually keeping safety rules have higher safety awareness(F=14.285, p=0.000). 3. When parents give safety education to their children as often as possible, the safety awareness level of students was high(F=5.257, p=.006). 4. Students having an accident have no safety education experience than students having no accident(p<0.05). They have never had safety education from a health teacher. There was statistical significance(p<0.01). Conclusions: Accordingly, we need to make students have safety attitude to prevent safety accidents. To achieve it, safety awareness has to be inspired. Systematic and various education programs that can give connected education with local community network to the students and parents is required.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.9
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• pp.814-820
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• 2015

In this paper, A high selective dual-band bandpass filter was proposed using a dual-mode ring resonator with two short-circuited stubs. For dual-mode resonance, the ring resonator is directly connected with non-orthogonal feed-lines via coupling capacitors. Two short-circuited stubs which are unequal lengths are simultaneously placed at two corners along the two symmetry plane of the ring resonator in order to obtain dual-band responses. Because the feeding angle perturbated ring resonator of the proposed dual-band bandpass filter has the symmetrical structure, Even/Odd mode analysis can be well applied to extract the scattering parameters and transmission zero frequencies. The proposed dual-band bandpass filter was designed and fabricated for WLAN(Wireless Local Area Network) application of IEEE 802.11n standard. The measured results showed a good agreement with the simulation results, and it should be well applied not only for WLAN applications but also for any other communication systems.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.11
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• pp.103-104
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• 1992

Automatic transmission of data from the blood analyzer to the request site is one of the most important part in hospital computerization. We have developed a system to automatically transmit the data from the atrial blood gas analyzer. In this system, HOST computer, FILE server, LAN(Local Area Network), 3270 Emulator and Multi-port card were integrated. Also, 3 blood gas analyser(NOVA Inc., USA) were connected to a single multi-port card which is attached in a personal computer for data acquisition. When specimen is collected from sampling sites, it is transfered to the lab. After analysis, the result is transmitted to the personal computer via serial communication between machine and multi-port card using interrupt method. Then, the patient's information (Name, Sex, etc.) is obtained from the HOST computer througth the emulator. The combined data(patient information & lab data) is transmitted to the each request site via LAN automatically. From the collected data, patient's previous data could be reviewed, and it could be used for the various statistics and the flow chart for clinical research. Also, we found that this system reduces the personal labor.

• Progress in Superconductivity
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• v.7 no.2
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• pp.114-119
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• 2006

High critical current density, high n value, multiple faults endurances, and fast recovery characteristics of YBCO thin films are very attractive characteristics for developing resistive type superconducting fault current limiters. But due to the limited current and voltage ratings of one YBCO module, it is needed to construct series and parallel module connections for high capacity electric networks. Especially for distribution network, more than 30 units should be connected in series to meet voltage level. So in order to construct distribution-level superconducting fault current limiter, simultaneous quench in one YBCO thin films should be realized, and furthermore, quench should be occurred in all fault current limiting units equally to avoid local heating and failures. In this paper, we proposed optimum design of YBCO thin films for fault current limiting module and technical method using shunt resistor to achieve simultaneous quench between multi current limiting units. From the analytical and the experimental results, optimal current path and thickness of shunt material was determined for YBCO thin films and shunt resistor between modules was developed. Finally, 14 kV one phase resistive fault current limiter using multi YBCO thin films was constructed and it was possible to get satisfactory test results.