• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.243-244
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• 2019

본 논문에서는지속 가능한 IoT Platform을 개발 하였다. 개발된 IoT(Internet of Things) Platform은 센서를 제어하는 특정 시스템과의 통신을 통한 제어 및 데이터 전달에 용이하고, 제한된 통신 환경 및 낮은 전력에서도 지속적인 작동이 가능하여 가용성(Availability)과 확장성(Extensibility)이 뛰어나다. 본 논문에서는 지속 가능한 IoT Platform의 테스트를 위해 클라우드 컴퓨팅 플랫폼인 AWS EC2(Amazon Elastic Compute Cloud, EC2)에 구축하였으며, DataBase 서버로는 오픈 소스 관계형 데이터베이스 관리 시스템인 MariaDB를 선정하였으며, 센서를 제어하는 특정 시스템인 스마트 미러 시스템(Smart Mirror System)과 미세먼지 제어 시스템(Air Quality Control System)에 기존의 Google IoT Platform에서 사용되는 MQTT Protocol(Message Queuing Telemetry Transport Protocol)와 지속 가능한 IoT Platform를 위해 개발된 TCP/IP Protocol를 사용하여 비교했다. 개발된 IoT Platform은 UTM(Unmanned Aircraft System Traffic Management)으로 확장할 계획이다.

• Convergence Security Journal
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• v.23 no.1
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• pp.3-8
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• 2023

Multi-domain optical transport networks are not fundamentally interoperable and require an integrated orchestration mechanism and path provision mechanism at the entire network level. In addition, ensuring network survivability is one of the important issues. MPLS-TP (Multi-Protocol Label Switching-Transport Profile) defines various protection/recovery methods as standards, but does not mention how to calculate and select protection/recovery paths. Therefore, an algorithm that minimizes protection/recovery collisions at the optical circuit packet integrated network level and calculates and sets a path that can be rapidly protected/recovered over the entire integrated network area is required. In this paper, we proposed an algorithm that calculates and sets up a path that can be rapidly protected and restored in a T-SDN network composed of multiple ring-mesh topology.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.11_12
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• pp.654-662
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• 2005

Mobile portable devices for wireless network solely depend on a limited battery power. Therefore, we need to design for wireless communication protocols with an energy efficiency. TCP-Westwood is one of the most important approaches on TCP performance improvement in wireless environments that estimates the available bandwidth by using the sampling mechanism. The advantage is that data can be transmitted efficiently using the estimation of available bandwidth. However, when the sender with TCP-Westwood is in a wireless environment, it does not consider of the sampling mechanism operation. In this thesis, a new energy saving transport protocol, called E2TP(Energy Efficient Transport Protocol), is proposed to solve problems which occur when the sender with TCP-Westwood is in a wireless environment. Also, when there are packet loss while doing frequent link error in a wireless environment, E2TP provides the instantaneous segment size adjustment for a more efficient data retransmission. The simulation result proves that the proposed E2TP has better performance in energy efficiency and throughput than both TCP and TCP-Westwood.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.5
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• pp.859-870
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• 2020

The MQTT-SN (Message Queuing Telemetry Transport-Sensor Network) protocol is a message transmission protocol used in a sensor-based Internet of Things (IoT) environment. This MQTT-SN protocol is a publish-subscribe model with a broker in the middle of message transmission, and each IoT device sends and receives messages through an intermediary when delivering messages. However, the MQTT-SN protocol does not provide security-related functions such as message security, mutual authentication, access control, and broker security. Accordingly, various security problems have recently occurred, and a situation in which security is required has emerged. In this paper, we review the security requirements of MQTT-SN once again, and propose a modified protocol that improves security while satisfying the constraints in the environment where the resource of IoT to which this protocol is applied is limited. Unlike the existing protocol, the security field and authentication server have been added to satisfy the security requirements. In addition, the proposed protocol is actually implemented and tested, and the proposed protocol is evaluated for practical use in terms of energy consumption.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.5
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• pp.619-627
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• 1999

To support multimedia services between network domains with different environments, it is required to map the functionalities in many aspects. In this paper, we implemented interworking gateway which provides protocol conversion and QoS(Quality of Service) adaptation to interwork DAVIC services based on ATM(Asynchronous TRansfer Model )network and Internet AV services. The interworking gateway converts RTSP(Real-Time Streaming Protocol ) message into DSM-CC(Digital Storage Media Command & Control) messages to control the stream that is served in ATM network, and transmits data stream by using RTP(Real-Time Transport Protocol) The interworking gateway provides QoS adaptation functionalities by QoS monitoring and MPEG filtering to meet the variation of network bandwidth.

• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.436-449
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• 2016

This paper compares the transport overhead of MMT (MPEG Media Transport) with that of MPEG-2 TS (Transport Stream). MPEG-2 TS is globally used in multiplexing compressed audio and video data in digital broadcast industry, including areas of DTV (Digital Television), IPTV (Internet Protocol Television), and DMB (Digital Multimedia Broadcasting). It was the early 1990s when MPEG-2 TS standard was established. After more than two decades of years since its first establishment, many parts of MPEG-2 TS turned out to be inappropriate to today's broadcast and communication environment. Given the situations, in 2014 MPEG (ISO/IEC JTC 1 SC 29/WG 11) standardized MMT as the next-generation multimedia transport standard hopefully that can replace MPEG-2 TS. In this paper, with assumptions of broadcast service scenarios we applied both MMT and MPEG-2 TS to each scenario and we calculated their transport overheads. We used a software program that counts the transport overhead, which was developed in our laboratory for this paper. And we conducted a comparative analysis based on the calculated result of transport overhead.

• Journal of Korean Critical Care Nursing
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• v.15 no.1
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• pp.1-12
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• 2022

Purpose : This study aimed to identify the status of intrahospital transport (IHT) of critically ill patients and provide baseline data to form recommendations for safer transport. Methods : Data were collected from 141 intensive care unit (ICU) nurses who attended national conferences between February and August, 2018. The collected data were analyzed using descriptive statistics and ANOVA, and post-hoc analysis was conducted with the Scheffé and Games-Howell tests. Results : Of the nurses surveyed, 61.7% answered that their workplace had a transport guideline. In terms of the experience of ICU nurses, 31.2% of respondents answered that they had received training on IHT. This result indicated that the degree of implementation of the guidelines for IHT was generally high, but some, including guidelines on personnel, equipment, and monitoring, were not. Guidelines of IHT were well observed when the institutes had specific guidelines for IHT of critically ill patients with specified transport grades, a scoring system to assess stability of a patient, a checklist and a protocol for action in case of problems, and when healthcare providers were provided with training. Conclusion : These results suggest that organized infrastructure, such as a transport guideline with transport grades, a checklist to improve the implementation of guidelines, and a protocol for coping with a problem, should be provided for safe transport. Additionally, effective education and evaluation to improve the competency of staff participating in the transport of patients will help reduce the occurrence of adverse events in intensive care transport in hospitals and promote patient safety.

• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.154-157
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• 2008

유비쿼터스 센서 네트워크에서 전력 효율을 높이는 것은 매우 중요한 과제이다. 노드의 전력 소비를 줄이기 위해 다양한 mac protocol 들이 제안되어 왔고, 본 논문에서는 ns2(network simulator) tool을 이용하여 Wei Ye, John Heidemann, Deborah Estrin 이 2002년에 발표한 S-MAC Protocol 의 전력효율을 기존의 IEEE 802.11 MAC 과 비교하였다.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.211-214
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• 2005

There are emerging many eScience applications. More and more scientists want to collaborate on their investigation with international partners without space limitation by using these applications. Since these applications have to analyze the massive raw data, scientists need to send and receive the data in short time. So today's network related requirement is high speed networking. The key point of network performance is transport protocol. We can use TCP and UDP as transport protocol but we use TCP due to the data reliability. However, TCP was designed under low bandwidth network, therefore, general TCP, for example Reno, cannot utilize the whole bandwidth of high capacity network. There are several TCP variants to solve TCP problems related to high speed networking. They can be classified into two groups: loss based TCP and delay based TCP. In this paper, I will compare two approaches of TCP variants and propose a hybrid approach for high speed networking.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.107-115
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• 2005

For effective IP based service implementation on the wireless network environments, wireless network including the ITS network have to support QoS guaranteed protocol such as a RSVP. RSVP is a resource reservation protocol for Internet environment, and its scalability makes easy to implement RSVP over the various IP transport technologies. But for the If based ITS wireless network environment, RSVP is not suitable, since by its path setup procedure characteristic. In the wireless access network for ITS service, when a mobile node moves to other domain it must perform registration procedure. But the registration procedure is time consuming steps, so if a RSVP session was already established in the previous domain, the RSYP session may be disconnected and the time to re establish a new RSVP session is long enough to cause serious packet loss. In this paper, we propose a pre-path reservation mechanism for applying the RSVP in wireless access networks for ITS. In the pre-path reservation mechanism, the resource reservation procedure occurred during a mobile node's handoff time. An access point in wireless access network performs this procedure when the mobile node attempts handoff The access point executes pre-path reservation procedure as a proxy, since the mobile node does not have IP address until the address allocation procedure is finished in a new domain.