• Journal of Environmental Impact Assessment
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• v.30 no.1
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• pp.1-12
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• 2021

This study focused on verifying the identification of freshwater fish species in Korea using Environmental DNA (eDNA) technique. The research of DNA is increasing in the field of ecology, since this is more sensitive of identify rather than traditional investigation method. Which is difficult to detect species hidden in water and be easily influenced by diverse factors (sites, bad weather, researchers and so on). We applied the pilot test in aquarium (Freshwater Fish Ecological Learning Center in Yangpyeong, Gyeonggi Do), where freshwater fish species are inhabits. We conducted to sampling and analyzing the sixteen water samples (50 species from 7 orders and 13 families) using MiFish primer set. The results showed that 45 species (90%) was investigated by eDNA. It highlight that eDNA with universal primer is possible to detect freshwater fish species of Korean. However, the errors on species identification seems to be caused by the primer that be not suited perfectly and the pollution such as aquarium, sampling collectors.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.102-109
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• 2009

Purpose: Flash 3D (pixon(R) method; 3D OSEM) was developed as a software program to shorten exam time and improve image quality through reconstruction, it is an image processing method that usefully be applied to nuclear medicine tomography. If perfoming brain diamox perfusion scan by reconstructing subtracted images by Flash 3D with shortened image acquisition time, there was a problem that SNR of subtracted image is lower than basal image. To increase SNR of subtracted image, we use LEAP collimators, and we emphasized on sensitivity of vessel dilatation than resolution of brain vessel. In this study, our purpose is to confirm possibility of application of LEAP collimators at brain diamox perfusion tomography, identify proper reconstruction factors by using Flash 3D. Materials and methods: (1) The evaluation of phantom: We used Hoffman 3D Brain Phantom with $^{99m}Tc$. We obtained images by LEAP and LEHR collimators (diamox image) and after 6 hours (the half life of $^{99m}Tc$: 6 hours), we use obtained second image (basal image) by same method. Also, we acquired SNR and ratio of white matters/gray matters of each basal image and subtracted image. (2) The evaluation of patient's image: We quantitatively analyzed patients who were examined by LEAP collimators then was classified as a normal group and who were examined by LEHR collimators then was classified as a normal group from 2008. 05 to 2009. 01. We evaluate the results from phantom by substituting factors. We used one-day protocol and injected $^{99m}Tc$-ECD 925 MBq at both basal image acquisition and diamox image acquisition. Results: (1) The evaluation of phantom: After measuring counts from each detector, at basal image 41~46 kcount, stress image 79~90 kcount, subtraction image 40~47 kcount were detected. LEAP was about 102~113 kcount at basal image, 188~210 kcount at stress image and 94~103 at subtraction image kcount were detected. The SNR of LEHR subtraction image was decreased than LEHR basal image about 37%, the SNR of LEAP subtraction image was decreased than LEAP basal image about 17%. The ratio of gray matter versus white matter is 2.2:1 at LEHR basal image and 1.9:1 at subtraction, and at LEAP basal image was 2.4:1 and subtraction image was 2:1. (2) The evaluation of patient's image: the counts acquired by LEHR collimators are about 40~60 kcounts at basal image, and 80~100 kcount at stress image. It was proper to set FWHM as 7 mm at basal and stress image and 11mm at subtraction image. LEAP was about 80~100 kcount at basal image and 180~200 kcount at stress image. LEAP images could reduce blurring by setting FWHM as 5 mm at basal and stress images and 7 mm at subtraction image. At basal and stress image, LEHR image was superior than LEAP image. But in case of subtraction image like a phantom experiment, it showed rough image because SNR of LEHR image was decreased. On the other hand, in case of subtraction LEAP image was better than LEHR image in SNR and sensitivity. In all LEHR and LEAP collimator images, proper subset and iteration frequency was 8 times. Conclusions: We could archive more clear and high SNR subtraction image by using proper filter with LEAP collimator. In case of applying one day protocol and reconstructing by Flash 3D, we could consider application of LEAP collimator to acquire better subtraction image.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.3
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• pp.254-262
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• 2013

This paper proposes FMT(Filtered Multi-Tone)-based digital radio implementation algorithms and the results obtained by various field tests especially in terms of transmitter characteristics. In this study, we predefined frame structure and protocols used for the CSTDMA(Carrier Sensing Time Division Multiple Access) scheme, designed digital filters and RF front end to fulfill the system characteristics such as the spectral mask and processing delays given by the Recommendation ITU-R M.1842-1. The proposed system supports exchange of data for e-Navigation with the usage of wider channel of 50-100kHz bandwidth, Turbo coding and FMT modulation. Furthermore, the common Ethernet protocol makes connection to local WLAN(Wireless Local Area Network) on board the ship for other data services.

• Journal of KIISE:Information Networking
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• v.35 no.4
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• pp.301-310
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• 2008

In the existing literature, the handover process reveals numerous problems manifested by high movement detection latency. FMIPv6 can reduce packet loss using a tunnel-based handover mechanism. However, this mechanism may cause performance degradation due to the out-of-sequence packets. Recently. Proxy Mobile IPv6 is proposed for network-based mobility management to reduce overhead in mobile node. PMIPv6 can decrease handover latency which related overhead in MN by using network agent. In this paper, we proposed optimized fast handover scheme called Fast Proxy Mobile IPv6 (EF-PMIPv6). The proposed EF-PMIPv6 can support fast handover using fast IAPP and ND schemes. Further, a mathematical analysis is provided to show the benefits of our scheme. In the analysis, various parameters are used to compare our scheme with the current procedures, while our approach focuses on the reduction of handover latency.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.85-92
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• 2020

Following the development of Internet of Things (IoT) technology, the scope of application of IoT technology is expanding to industrial safety areas that detect and prevent possible risks in outdoor environments in advance, away from improving the convenience of living in indoor environments. Although this expansion of IoT service provides many advantages, it also causes security problems such as data leakage and modulation, so research on security response strategies is being actively carried out. In this paper, the IoT-based road construction risk management system in outdoor environment is proposed as a research subject. As a result of investigating the security vulnerabilities of the low-power wide-area (LPWA, BLE) communication protocol applied to the research targets, the security vulnerabilities were identified in terms of confidentiality, integrity, and availability, which are the three major elements of information security, and countermeasures for each vulnerability were proposed. This study is meaningful in investigating and analyzing possible vulnerabilities in the operation of the IoT-based risk management system and proposing practical security guidelines for each vulnerability.

• The KIPS Transactions:PartD
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• v.13D no.2 s.105
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• pp.175-182
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• 2006

Radars are used to detect the motion of the low flying enemy planes in the military. Radar-detected raw data are first processed and then inserted into the ground tactical C4I system. Next, these data we analyzed and broadcasted to the Shooter system in real time. But the accuracy of information and time spent on the displaying and graphical computation are dependent on the operator's capability. In this paper, we propose the Flying Object Tracking Management System that allows the displaying of the objects' trails in real time by using data received from the radars. We apply the coordinate system translation algorithm, existing communication protocol improvements with communication equipment, and signal and information computation process. Especially, radar signal duplication computation and synchronization algorithm is developed to display the objects' coordinates and thus we can improve the Tactical Air control system's reliability, efficiency, and easy-of-usage.

• Convergence Security Journal
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• v.13 no.2
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• pp.155-163
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• 2013

Connection hijacking attack using the vulnerability of the TCP protocol to redirect TCP stream goes through your machine actively (Active Attack). The SKEY such as one-time password protection mechanisms that are provided by a ticket-based authentication system such as Kerberos or redirection, the attacker can bypass.Someone TCP connection if you have access on TCP packet sniffer or packet generator is very vulnerable. Sniffer to defend against attacks such as one-time passwords and token-based authentication and user identification scheme has been used. Active protection, but these methods does not sign or encrypt the data stream from sniffing passwords over insecure networks, they are still vulnerable from attacks. For many people, an active attack is very difficult and so I think the threat is low, but here to help break the illusion successful intrusion on the UNIX host, a very aggressive attack is presented. The tools available on the Internet that attempt to exploit this vulnerability, known as the recent theoretical measures is required. In this paper, we propose analysis techniques on a wireless network intruder detection.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.183-186
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• 2006

It is studied the implementation possibility of some encryption algorithms which meet the performance requirements in the smart card used in the TETRA system End-to-End Encryption. It is measured the operation time of the algorithm in the smart card which has 32 bit smart card controller made by Samsung Electronics. The algorithms used in the performance comparison are AES, ARIA, 3DES, SEED, IDEA which are the domestic or international standards. The input and output time of the smart card are measured using the smart card protocol analyzer. The pure algorithm operation time is calculated by the repeated algorithm operations. This measurement results can be used as the criteria for the selection of algorithm which will be used in the TETRA End-to-End encryption system. The algorithm which has better performance can be used for the implementation of additional functions in the smart lard, because of the enough time margin.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.1001-1008
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• 2019

A high-quality pseudorandom sequence generation is an important part of many cryptographic applications, including encryption protocols. Therefore, a pseudorandom number generator (PRNG) is an essential element for generating key sequences in a cryptosystem. A PRNG must effectively generate a large, high-quality random data stream. It is well known that the bitstreams output by the CA-based PRNG are more random than the bitstreams output by the LFSR-based PRNG. In this paper, we prove that the complemented CA derived from 90/150 maximum length cellular automata(MLCA) is a MLCA to design a PRNG that can generate more secure bitstreams and extend the key space in a secret key cryptosystem. Also we give a method for calculating the cell positions outputting a nonlinear sequence with maximum period in complemented MLCA derived from a 90/150 MLCA and a complement vector.

• Journal of the Korea Society of Computer and Information
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• v.14 no.5
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• pp.149-156
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• 2009

Korean WiBro becomes international standard to IEEE 802.16e, and We are carrying out a WiBro network business from capital regions. We executed eavesdropping about voices and messenger program and the VoIP which frequently happened in WiBro networks at these papers. We have a lot in common with the Wireshark which is a packet collection and an analyzer, and We execute eavesdropping, and We reproduce eavesdropping data with bases to a SIP, H.263, TCP, UDP protocol through packets. In time of a copy of a packet negative the VoIP which verify time with bases, and was eavesdropped on integrity packet and a X-Lite call record, be matched that a packet is counterfeit forgery did not work, and We demonstrate, and verify integrity. The data which integrity was verified put in a seaming envelope, and we prepare so as it is to a liver of investigator, and execute, and to be able to do use to proof data after seaming in courts in order to utilize as criminal investigation data.