• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.86-94
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• 2010

This paper proposed an authentication interworking protocol (AIP) based on IEEE 802.21 MIH in the heterogeneous networks. The proposed AIP using the RSA signature reduces handover delay time and communication message overhead when the mobile node moves between the heterogeneous networks. It defines new AIP TLV in MIH frame format and uses the MIH Information Server (MIHIS) for proxy signature issue instead of the authentication server for the heterogeneous networks. For low handover delay, the proposed AIP performs pre-authentication processes with MIH protocol before layer 2 handover. Also, this paper analyzed the performance of the handover and compared with the non-secure MIH protocol.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.7
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• pp.46-56
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• 2002

In this paper, we describe a hardware-software co-verification methodology and environment in developing a mobile station modem chip for cdma2000 1x which is one of the 3rd generation mobile communication standards. By constructing an efficient co-verification environment for a register-transfer-level hardware model and a physical-layer software model combining a channel link simulator and a versatile test-bench, we can drastically reduce both time and cost for developing a complex three-million-gate class system integrated circuit.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.12
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• pp.90-97
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• 1999

Recently, there have been many researches to automate processing and analysing image data in medical field, due to the advance of image processing techniques, the fast communication network and high performance hardware. In this paper, we design and implement the system based on the multi-layer neural network model to be able to analyze, differentiate and count blood cells in the peripheral blood image. To do these, we segment red and white-blood cell in blood image acquired from microscope with CCD(Charge-coupled device) camera and then apply the various feature extraction algorithms to classify. In addition to, we reduce multi-variate feature number using PCA(Principle Component Analysis) to construct more efficient classifier. So, in this paper, we are sure that the proposed system can be applied to a pathological guided system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.6
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• pp.2422-2443
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• 2020

This paper studies a single-user Mobile Edge Computing (MEC) system where mobile device (MD) includes an application consisting of multiple computation components or tasks with dependencies. MD can offload part of each computation-intensive latency-sensitive task to the AP integrated with MEC server. In order to accomplish the application faultlessly, we calculate out the optimal task offloading strategy in a time-division manner for a predetermined execution order under the constraints of limited computation and communication resources. The problem is formulated as an optimization problem that can minimize the energy consumption of mobile device while satisfying the constraints of computation tasks and mobile device resources. The optimization problem is equivalently transformed into solving a nonlinear equation with a linear inequality constraint by leveraging the Lagrange Multiplier method. And the proposed dual Bi-Section Search algorithm Bi-JOTD can efficiently solve the nonlinear equation. In the outer Bi-Section Search, the proposed algorithm searches for the optimal Lagrangian multiplier variable between the lower and upper boundaries. The inner Bi-Section Search achieves the Lagrangian multiplier vector corresponding to a given variable receiving from the outer layer. Numerical results demonstrate that the proposed algorithm has significant performance improvement than other baselines. The novel scheme not only reduces the difficulty of problem solving, but also obtains less energy consumption and better performance.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.99-109
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• 2016

This paper presents a method for generating spatiotemporal images to detect the leukocyte motions in a microvessel. By using the constraint that the leukocytes move along the contour line of a blood vessel wall, the method detects leukocyte motions and then generates spatiotemporal images. the translational motion by a movement in vivo is removed first by the template matching method. Next, a blood vessel region is detected by the automatic threshold selection method to binarize the temporal variance image, then a blood vessel wall's contour is expressed by B-spline function. With the detected blood vessel wall's contour as an initial curve, the plasma layer of the best accurate position is determined to be the spatial axis by snake. Finally, the spatiotemporal images are generated. The experimental results show the spatiotemporal images are generated effectively through the comparison of each step of three image sequences.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1297-1307
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• 2013

Several multi-hop applications developed for vehicular ad hoc networks use broadcast as a means to either discover nearby neighbors or disseminate useful traffic information to othet vehicles located within a certain geographical area. However, the conventional broadcast mechanism may lead to the so-called broadcast storm problem, a scenario in which there is a high level of contention and collision at the link layer due to an excessive number of broadcast packets. To solve broadcast storm problem, we propose an RPB-MACn-based LV-CAST that is a vehicular broadcast algorithm for disseminating safety-related emergency message. The proposed LV-CAST identifies the last node within transmission range by computing the distance extending on 1 hop from the sending node of an emergency message to the next node of receiving node of the emergency message, and the last node only re-broadcasts the emergency message. The performance of LV-CAST is evaluated through simulation and compared with other message dissemination algorithms.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.61-68
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• 2004

Wireless mobile communication systems request high speed mobility and high speed data transmission capability. In order to meet the requirements, OFDM(Orthogonal Frequency Division Multiplex) is mainly adopted in the physical layer of the wireless systems. In commercial wireless mobile systems, IEEE802.(11a, 16e, etc) series seem to be used as the modulation method. For supporting multiple air-interfaces in a wireless mobile system, different kinds of OFDM based modulation methods should be supported in one modem chip. It requires a variable point IFFT/FFT or reconfigurable IFFT/FFT processor. In this paper, we propose the design method of a reconfigurable IFFT/FFT processor. In addition, it is shown that a reconfigurable IFFT/FFT processor can he implemented by using the proposed method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.11
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• pp.28-33
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• 2002

In this paper, the impedance-tuned monopole microstrip antenna designed for PCS is analyzed using finite difference time domain(FDTD) method. The perfectly matched layer(PML) absorbing material condition proposed by Berenger is used for the truncation of finite difference time domain lattice. A Gaussian pulse is selected as an excitation signal and a resistive voltage source model is used to reduce the error caused by the reflection waves. The FDTD method is inherently a near field technique. Therefore, the near field to far field transformation is need to compute far field antenna parameters such as radiation patterns and gain. The near field to far field transformation can be done both in the time domain and the frequency domain. We use the frequency domain transformation to compute the far field radiation patterns at single frequency. All the numerical results obtained by the FDTD method are compared with simulation results using the HFSS software. Good agreements are obtained in all cases.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1384-1393
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• 2008

In this paper, we analyzed the multilayer structure with lossy metamaterials using ABCD Matrix method to get the transmission characteristics. Compared to the recursive method which cannot be used to analyze the lossy characteristics of multilayer structure because of its complexity, we used the ABCD matrix method is easy to apply because of its matrix chain concepts for arbitrary number of multilayer structure and lossy material. To verify the results of this paper, we used both for multilayer dielectric and metamaterial, respectively, and obtained the same results. Multilayer structure with lossy metamaterial showed minimized ripple and broadband transmission compared to dielectric multilayered structure. This can be used in various applications as antenna radome and shielding material, etc.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.547-554
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• 2005

Ethernet has been given a greater attention recently due to tendency of unifying most of transmission technique to ethernet. This paper studied the design of MAC which contains high layer interface, transmit engine, flow control block, receive engine, reconciliation sublayer, configuration block, statistics block, and XGMll interface block. Performance evaluation was performed using C language for 10cbps ethernet Data Link to design the optimum hardware, then internal FIFO and initial parameters were evaluated. When offered load is $95\%$, the size of the internal FIFO is required 512-word. When offered load is $97\%$, the size of the internal FIFO is required 1024-word. Based on the result of performance evaluation, MAC was designed in VHDL Language and verified using simulator. MAC core that processes 64-bit data, operates at 168.549MHz and hence supports the maximum 10.78Gbps. The designed MAC core is applicable to an area that needs a high-speed data processing of 10Gbps or more.