• Journal of Internet Computing and Services
• /
• v.9 no.1
• /
• pp.159-170
• /
• 2008

The ubiquitous network revolution is beginning with the onset of digital convergence, whereby computers, horne appliances, and communications and broadcast media are being unified into digital media with the founding of the information super high speed. This technical advancement is creating a new culture and a new space and accelerating society's transition to the new and unique social paradigm of a 'ubiquitous society'. In particular, studies on ubiquitous communications are well underway. Lately, the focus has been on the Bluetooth technology due to its applicability in various environments. Applying Bluetooth connectivity to new environments such as ubiquitous or sensor networks requires finding new ways of using it. Thus, the scalable Bluetooth piconet scheme with independent slave device is proposed. It follows from work by Sea et al. But extended scatternet is not considered is Kiisc05 paper. Therefore, we propose secure bridge connection scheme for scalable Bluetooth scatternet.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.6C
• /
• pp.651-657
• /
• 2006

This paper propose the technique for the execution authentication of digital signature with TTS(traceable trust server) to guarantee the safe execution of mobile agents. That is to say, it is focused on improving the processing speed of systems and the traffic of network which are problems in the existing studies. The digital signature is used to guarantee the efficient and safe execution and the integrity of mobile agents. The certificate of it is chained with synthesis function, cryptographic algorithm based on public key, and hash function. And white hosts can be protected against the threat of being used maliciously. Then, we prove the efficiency of system overhead and the traffic of network by the analysis. In case the certificate chain of a digital signature is used, the safe execution of mobile agents can be protected against attackers that wish to insert a newly created certificate after cutting off the chain after striking space key 2 times.

• Journal of KIISE
• /
• v.43 no.9
• /
• pp.1034-1042
• /
• 2016

Together with machine-learning frameworks, area-based imagery registration techniques can be easily applied to diverse types of image pairs without predefined features and feature descriptors. However, feature detectors are often used to quickly identify candidate image patch pairs, limiting the applicability of these registration techniques. In this paper, we propose a ConvNet (Convolutional Network) "Dart" that provides not only the matching metric between patches, but also information about their distance, which are helpful in reducing the search space of the corresponding patch pairs. In addition, we propose a ConvNet "Fad" to identify the patches that are difficult for Dart to improve the accuracy of registration. These two networks were successfully implemented using Deep Learning with the help of a number of training instances generated from a few registered image pairs, and were successfully applied to solve a simple image registration problem, suggesting that this line of research is promising.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.6
• /
• pp.1009-1018
• /
• 2017

We developed new Digital Sampler for KVN(: Korean VLBI Network). The sampler has 1024MHz sampling frequency with 2bits/sample. The sampler's input reference frequencies are 1pps(: pulse per second) and 10MHz, also UTC(: Universal Time Coordinated) time information out with 1PPS signal, synchronized. The output of sampling data is adapted VSI(: VLBI Standard Interface) specification including the time information. In order to confirm the performance of the sampler, we carried out the astronomical radio observation test in Ulsan Radio Observatory of KVN. It was confirmed the stable performance. In this paper, We introduce the new developed sampler and present the observational test result.

• Convergence Security Journal
• /
• v.16 no.3_2
• /
• pp.33-42
• /
• 2016

While evolving information-oriented society provides a lot of benefits to the human life, new types of threats have been increasing. Particularly, cyber terrorism, happen on the network that is composed of a computer system and information communication network, and the mean and scale of damage has reached a serious level. In other words, it is hard to locate cyber terror since it occurs in the virtual space, not in the real world, so identifying "Who is attacking?" (Non-visibility, non-formulas), or "Where the attack takes place?" (trans-nation) are hard. Hackers, individuals or even a small group of people, who carried out the cyber terror are posing new threats that could intimidate national security and the pace and magnitude of threats keep evolving. Scale and capability of North Korea's cyber terrorism are assessed as world-class level. Recently, North Korea is focusing on strengthen their cyber terrorism force. So improving a response system for cyber terror is a key necessity as North Korea's has emerged as a direct threat to South Korean security. Therefore, Korea has to redeem both legal and institutional systems immediately to perform as a unified control tower for preemptive response to cyber terrors arise from North Korea and neighboring countries.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2002.11a
• /
• pp.251-254
• /
• 2002

In the design of mobile wireless communication system, the location of BTS(Base Transciver Stations), RSC(Base Station Controllers), and MSC(Mobile Switching Center) is one of the most important parameters. Designing wireless communication system, the cost of equipment is need to be made low by combining various, complex parameters. We can solve this problem by combinatorial optimization algorithm, such as Simulated Annealing, Tabu Search, Genetic Algorithm, Random Walk Algorithm that have been extensively used for global optimization. This paper shows the four kind of algorithms which are applied to the location optimization of BTS, BSC, and MSC in designing mobile communication system and then we compare with these algorithms. And also we analyze the experimental results and shows the optimization process of these algorithms. As a the channel of a CDMA system is shared among several users, the receivers face the problem of multiple-access interference (MAI). Also, the multipath scenario leads to intersymbol interference (ISI). Both components are undesired, but unlike the additive noise process, which is usually completely unpredictable, their space-time structure helps to estimate and remove them.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.2
• /
• pp.185-191
• /
• 2008

Most threats of WLAN are easily caused by attackers who access to the radio link between STA and AP, which involves some Problems to intercept network communications or inject additional messages into them. In comparison with wired LAN, severity of wireless LAN against threats is bigger than the other networks. To make up for the vulnerability of wireless LAN, it needs to use the Intrusion Detection System using a powerful intrusion detection method as SVM. However, due to classification based on calculating values after having expressed input data in vector space by SVM, continuous data type can not be used as any input data. In this paper, therefore, we design the IDS system for WLAN by tuning with SVM and data-mining mechanism to defend the vulnerability on certain WLAN and then we demonstrate the superiority of our method.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.2
• /
• pp.386-394
• /
• 2017

FANET is an ad hoc network formed among the unmanned aircraft in the three-dimensional space for data transfer. Most of the research on FANET application has focused on the use of the camera sensor mounted on the unmanned aircraft to collect data from the ground, and process and delivery of the data for a specific purpose. However, the research on the fusion of WBAN and FANET that collects the data of the human body and passes through the FANET has not been studied much until now. Therefore, in this study, we study the data transmission system that collects the human body data of people working in the areas that are vulnerable to communication difficulties and passes the collected data through the FANET. In particular we analyze the possible methods to transfer the emergency data of the body in the fusion network of WBAN and FANET and provide a data transfer model that can be transmitted most efficiently.

• Journal of the Society of Disaster Information
• /
• v.14 no.3
• /
• pp.315-324
• /
• 2018

Purpose: This paper propose a temporary indoor positioning scheme with devices of internet of things (IoT) for disastrous situations in places without the infrastructure of networks. Method: The proposed scheme is based on the weighted centroid localization scheme that can estimate the position of a target with simple computation. Results: It also is implemented with the IoT devices at the underground parking lot, where the network is not installed, of general office building. According to the experiment results, the positioning error was around 10m without a priori calibration process at $82.5m{\times}56.4m$ underground space. Conclusion: The proposed scheme can be deployed many places without the infrastructure of networks, such as parking lots, warehouses, factory, etc.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2006.05a
• /
• pp.595-598
• /
• 2006

In this letter, a compact rectangular spiral antenna is proposed. Instead of a center excitation of conventional spiral antennas, the proposed antenna is adopted a modified feed network, feeding at the end of the spiral. The matching circuit of $'{\sqsupset}'$ shape is added at the feeding point. With this matching circuit, we can easily match the input impedance well, without the limit of the space. The parameter which determines the circular wave characteristic is explained, and the design guideline of the proposed antenna is presented. We design a proposed antenna operating at 9.5 GHz. Its size is only $0.6\lambda_g\times0.6\lambda_g$. The simulated bandwidth of the input impedance $(S11\leq-10)$ is 8.12% and that of $(AR\leq-3)$ is 4.62%, which is excellent characteristics as compared to its simple structure.