• Journal of KIISE:Computing Practices and Letters
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• v.15 no.11
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• pp.846-850
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• 2009

Recently, wireless sensor networks have found their way into a wide variety of applications and systems with vastly varying requirements and characteristics such as environmental monitoring, smart spaces, medical applications, and precision agriculture. The sensor nodes are battery powered. Therefore, the energy is the most precious resource of a wireless sensor network since periodically replacing the battery of the nodes in large scale deployments is infeasible. Energy efficient mechanisms for gathering sensor readings are indispensable to prolong the lifetime of a sensor network as long as possible. There are two energy-efficient approaches to prolong the network lifetime in sensor networks. One is the compression scheme to reduce the size of sensor readings. When the communication conflict is occurred between two sensor nodes, the sender must try to retransmit its reading. The other is the MAC protocol to prevent the communication conflict. In this paper, we propose a novel approaches to reduce the size of the sensor readings in the MAC layer. The proposed scheme compresses sensor readings by allocating the time slots of the TDMA schedule to them dynamically. We also present a mathematical model to predict latency from collecting the sensor readings as the compression ratio is changed. In the simulation result, our proposed scheme reduces the communication cost by about 52% over the existing scheme.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.919-939
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• 2021

As a next-generation communication technology, 5G networks are capable of handling large amounts of traffic based on higher speeds, shorter communication delays, and higher connectivity compared to 4G networks. In this 5G network environment, base stations are installed all over the city at high density due to their characteristics, and are connected to user terminals to provide services. Therefore, if the base station is damaged by a malicious attacker, it is expected to cause great damage to users and society as a whole. So the need for secure communication equipment such as 5G base stations has emerged. Therefore, in this paper, we propose the security functional requirements derived using threat modeling, a systematic methodology for 5G base stations, and the security assurance requirements at the level that can cope with the backdoor issues. The security requirements proposed in this paper can be used for base station design and development to construct a secure network environment as a security evaluation standard for 5G base stations.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.41-46
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• 2023

Human urine is a process of excreting waste products in the blood, and it is easy to collect and contains various substances. Urinalysis is used to check for diseases, health conditions, and urinary tract infections. There are three methods of urinalysis: physical property test, chemical test, and microscopic test, and chemical test results can be easily confirmed using urine test strips. A variety of items can be tested on the urine test strip, through which various diseases can be identified. Recently, with the spread of smart phones, research on reading urine test strips using smart phones is being conducted. There is a method of detecting and reading the color change of a urine test strip using a smartphone. This method uses the RGB values and the color difference formula to discriminate. However, there is a problem in that accuracy is lowered due to various environmental factors. This paper applies a deep learning model to solve this problem. In particular, color discrimination of a urine test strip is improved in a smartphone using a lightweight CNN (Convolutional Neural Networks) model. CNN is a useful model for image recognition and pattern finding, and a lightweight version is also available. Through this, it is possible to operate a deep learning model on a smartphone and extract accurate urine test results. Urine test strips were taken in various environments to prepare deep learning model training images, and a urine test service application was designed using MobileNet V3.

• Journal of the Korea Society of Computer and Information
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• v.14 no.3
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• pp.121-131
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• 2009

BcN provides a wide variety of high-quality multimedia services such as broadcasting and communication convergence services. But the quality degeneration is observed in BcN when we use broadcasting and communication convergence service via more than one network of different internet service providers. In this paper, a QoS management system which is able to measure and maintain objectively the quality-related information in overall networks is proposed. The proposed QoS management system is tested on the pilot networks of BcN consortiums by measuring the quality of voice and video experienced by the actual users of the commercial video phone services. The result of the experiment shows that it is possible to figure out service qualify between a user and a service provider by analyzing the information from agents. The per-service traffic information collected by probes is proved to be useful to pinpoint the party responsible for the loss of the service qualify in case of the services including different service providers. As the result of the experiment, it is shown that the proposed QoS management system would play a key role of resolving the quality dispute, which is one of the important issues of QoS-guaranteed BcN.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.754-762
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• 2021

Seamless wireless communication network access technology enables users to guarantee service continuity. Hence, it is necessary for disaster situations in which network service may be interrupted. The Multi-path router is a technology to improve network stability and strengthen field operability, particularly in a disaster environment where network failure can occur by providing high-performance data transmission using multi-communication networks and network security by VPN-based wireless IP. In this paper, a prototype system for an MPR-based wireless communication network was proposed to improve the operation performance for disaster field investigation applications. A comparative experiment was performed on various data transmission performances with the existing single wireless communication network. In addition, another experiment was conducted by measuring the data packet transmission and receiving performance in the existing/new wireless communication system first and then assessing the UDP transmission performance in a single router environment to understand the transmission capability of the new MPR. The experimental results showed that the sending and receiving performance was improved by approximately double that of the existing single wireless communication system. The proposed prototype system is expected to allow users to share and disseminate collected on-site data more quickly and efficiently during a disaster site investigation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12C
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• pp.1123-1130
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• 2009

The advances in networking technology and importance of multimedia communication require real time transaction. In many applications, high reliable real-time communications are required more frequently. In this paper, we propose a reliable communication in cube-based multi -computer using the safety vector. Each node in a cube-based n dimensional multi-computer is associated with a safety vector of n bits, which is an approximated measure of the number and distribution of faults in the neighborhood. We propose an algorithm that can establish detour paths using the safety vector. The established detour paths are disjoint with the primary real-time channel. Therefore, our algorithm is more efficient than earlier proposed algorithms.

• Journal of information and communication convergence engineering
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• v.8 no.2
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• pp.219-222
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• 2010

An ubiquitous sensor network (USN) system to monitor the bio information and the emergency of the elderly in the silver town is presented. The USN system consists of the sensor node platforms based on MCU of Atmage128L and RF Chip of CC2420 satisfying IEEE 802.15.4, which includes the bios sensor module such as the electrocardiogram (ECG) sensor and the temperature sensor. Additionally, when an emergency of the elderly is occurred in the silver town, the routing algorithm suitable to find and inform the location of the elderly is proposed, and the proposed routing algorithm is applied to the USN. To collect and manage the ECG data at the PC connected to the sink node, LabView software is used. The bio information and the emergency of the elderly can also be monitored at the client PC by TCP/IP networks in the USN system.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.191-198
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• 2003

Location tracking is used to keep track of the location information of a mobile terminal in an idle state for a call setup between mobile terminals. In this paper, we introduce a new location tracking strategy that utilizes spatial locality to have better performance than a movement based location tracking strategy. We reduce a lot of unnecessary location updates by updating the location information of a mobile terminal using the virtual movement path, which is generated after removing spatial localities in the actual movement path. Simulation results show that the proposed strategy greatly reduces the overall location tracking cost.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.175-177
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• 2005

무선 센서 네트워크에서는 배터리에 의존하는 수많은 센서 노드들로 구성이 된다. 이때, 물체들을 감지하기 위해서는 센서들은 켜져 있어야 하고, 수집한 데이터는 클러스터 헤드(Cluster Head)나 싱크(sink) 로 보내주어야 한다. 일련의 동작을 위해서 센서들은 않은 에너지를 소모하게 된다 이를 보완하기 위해서 LEACH 라는 방법을 이용하여, 클러스터 헤드 만이 싱크로 데이터를 전송하고, 에너지를 균일하게 소모하기 위한 기법을 사용한다. 본 논문에서는 기본적으로 LEACH 방법을 이용하면서, 이동체의 이동을 감지함에 있어서, 이동체의 예상 이동영역을 예측하여, 예상 이동영역내에 존재하지 않는 센서 노드들은 다음 라운드가 시작할 때까지 Sleep 하도록 하고. 예상 이동영역내에 있는 센서 노드들만 감지하도록 하여, 에너지의 소모를 줄였다. 이때 예상 이동영역은 싱크가 이전에 수집한 데이터로 계산하여, 이동체들의 정보를 모든 노드들에게 브로드 캐스트(Broadcast)하고, 매 라운드마다 클러스터 헤드선택까지는 LEACH 와 마찬가지로 모든 센서 노드들이 참여하지만, 이후 클러스터의 구성원이 되기 위해서는 예상 이동영역내에 존재해야 한다. 만약 해당 라운드에서클러스터 헤드가 되어도, 구성원이 존재하지 않는 다면 다시 Sleep 하도록 하여, 에너지 소모를 줄였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.142-147
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• 2006

As computers and networks become popular, distributing information on the Internet is common in our daily life. In the past, e-mail has been the primary choice of exchanging information, but instant messengers are gaining popularity abroad and domestically because of their nature of getting immediate reponses. However a instant messenger services have the exposure of data on internet but clients use them without recognizing their exposure. It's like phone tapping. The coding technology using Public Key Cryptosystem has developed the public key infrastructure to be able to do the services of Access-control, Authentication, Confidentiality, Integrity. and Non-repudiation with internet. It is a thesis that suggests the certification protocol in a instant messenger using PKI(Public Key Infrastructure) for secure communication.