• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.4
• /
• pp.325-336
• /
• 2013

FlashLinQ, one of the typical D2D communication systems developed by Qualcomm, considers a single-tone communication based distributed channel-aware link scheduling method to realize the link scheduling process with low control overheads. However, considering the frequency selective fading effect of practical multi-path channel, the single-tone based SIR estimation causes a critical scheduling error problem because the received single-tone signal has quite different channel gain at each sub-carrier location. In order to overcome this problem, we propose a novel link scheduling method based on CAZAC (Constant Amplitude Zero Auto-Correlation) sequence for D2D communication system. In the proposed method, each link has a unique offset value set for the generation of CAZAC sequences. CAZAC sequences with the cyclic offsets are transmitted using multiple sub-blocks in the entire bandwidth, and then each device can obtain nearly full-band SIR using a good cyclic cross-correlation property of CAZAC sequence.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.4
• /
• pp.617-623
• /
• 2018

In this paper, we propose a novel seamless video composition method based on shape matching and Poisson equation. Video composition method consists of video segmentation process and video blending process. In the video segmentation process, the user first sets a trimap for the first frame, and then performs a grab-cut algorithm. Next, considering that the performance of video segmentation may be reduced if the color, brightness and texture of the object and the background are similar, the object region segmented in the current frame is corrected through shape matching between the objects of the current frame and the previous frame. In the video blending process, the object of source video and the background of target video are blended seamlessly using Poisson equation, and the object is located according to the movement path set by the user. Simulation results show that the proposed method has better performance not only in the naturalness of the composite video but also in computational time.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7690-7697
• /
• 2015

This study is to reveal structural causal relationship of individual factors influencing association member's substantive payment in the economic view which is a critical factor of project implementation and identify its influence through simulation and actual proof analysis. As the results of analysis, the first, association member's substantive payment is decided to allow for the difference between special price for association members and general price and the profit arising between the time of approval of disposal plan and moving in. The second, on analysis of sensitivity of individual factors influencing association member's substantive payment, floor area ratio applied to project has the biggest influence. Association member's payment is also greatly influenced by the subject of cost allocation for establishing infrastructure in project area. The third, this study set up a structure model based on causal relationship among the factors deciding association member's payment and empirically examined influence and path of influence which the individual factors exercise. The result indicates that control elements and regional characteristic elements influence association member's payment through the medium of plan elements.

• The KIPS Transactions:PartC
• /
• v.10C no.6
• /
• pp.809-814
• /
• 2003

The multicast transmitting the real-time data to groups may easily have many attacks from abnormal attacks because it has many links as compared to the unicast. The existing group key management architectures for preventing these problems are designed for protocols suitable for a large scale. Thus these architectures applied to a small scale routing protocols may have many overheads with key distribution and a constant core tree. Therefore this paper proposes a groups key management protocol for a secure multicast in PIM-SM multicast group communication. The proposed method divide multicast groups with RO(Rendezvous-Point), and subgroup key managers are established in each RP and can be transmitted groups keys between senders and receivers, so the security cannel is set up for secure data transfer, And this does not have needs of the data translation for group keys and the new key distribution for path change. As a result of this, the data transmission time can be reduced.

• Journal of KIISE:Databases
• /
• v.33 no.2
• /
• pp.224-238
• /
• 2006

As XML became the standard of data exchange in the internet, the needs for effective query processing for XML data in streaming environment is increasing. Applying the existing database technique which processes data with the unit of tuple to the streaming XML data causes the out-of-memory problem due to limited memory volume. Likewise the cost for searching query path and accessing specific data may be remarkably increased because of special structure of XML. In a word it is unreasonable to apply the existing database system to the streaming environment that processes query for partial data, not the whole one. Thus, it should be able to search partial streaming data that rapidly satisfies join predicate through using low-capacity memory, based on a store technique suitable to streaming XML data. In this thesis, in order to study the store technique for low-capacity memory, the PCDATA and the CDATA-related parts, which can be used as predicate on join query, were fetched and saved. In addition, in an attempt to compare rapid join predicates, the range window of streaming XML data was set with the object of selectively joining windows that satisfies the query, based on Cardinality * and + among the structure information of DTD.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.2
• /
• pp.407-413
• /
• 2015

In this paper, a DFPA(decimal floating-point adder) designed a pipeline structure that uses a LZA(leading zero anticipator) to reduce critical route to shorten delay to improve the speed of operation processing. The evaluation and verification of performance of proposed DFPA applied the Flowrian tool with simulation and Cyclone III FPGA was set as the target on the Quartus II tool for the synthesis. The proposed method compared and verified to proposed the other method using same input data. As a result, the performance of proposed method is improved 11.2% and 5.9% more than L.K.Wang's method and etc.. Also, it is confirmed that improvement of operation processing speed and reduction of the number of delay elements on critical path.

• Journal of Korea Spatial Information System Society
• /
• v.10 no.3
• /
• pp.67-78
• /
• 2008

With the rapid development of wireless communication and mobile equipment, many applications for location-based services have been emerging. Moving objects such as vehicles and ships change their positions over time. Moving objects have their moving path, called the trajectory, because they move continuously. To monitor the trajectory of moving objects in a large scale database system, an efficient Indexing scheme to processed queries related to trajectories is required. In this paper, we focus on the issues of minimizing the dead space of index structures. The Minimum Bounding Boxes (MBBs) of non-leaf nodes in trajectory-preserving indexing schemes have large amounts of dead space since trajectory preservation is achieved at the sacrifice of the spatial locality of trajectories. In this thesis, we propose entry relocating techniques to reduce dead space and overlaps in non-leaf nodes. we present performance studies that compare the proposed index schemes with the TB-tree and the R*-tree under a varying set of spatio-temporal queries.

• Convergence Security Journal
• /
• v.18 no.5_2
• /
• pp.83-92
• /
• 2018

Korea is increasingly vulnerable to disasters due to changes in economic and social structure. In particular, there are a number of disadvantaged people, such as elderly people, disabled people, basic livelihood recipients, foreigners, multicultural families, etc. who are vulnerable to social problems due to aging, polarization and internationalization. These vulnerable people to disaster have difficulties in acquiring disaster information and to respond promptly by self-help. Of course, recent studies on vulnerable people to disaster have been steadily increasing, but discussions about foreigners have been relatively inadequate. This has led to a lack of understanding about the actual situation of disaster and coping methods. Once general situations set in, foreigners staying in Korea will suffer from a vicious cycle of policy-making from the viewpoint of Korean and difficulties in obtaining relevant information. In this study, we conducted in-depth interviews on the recognition and acquisition path of disaster information for foreign workers living in Korea. Based on the results of the interviews, we derived implications for practical information, such as ways to understand and actively utilize information media frequently visited by foreign workers in Korea.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.9
• /
• pp.1158-1165
• /
• 2021

This paper proposes a CNN accelerator which is optimized Pooling layer operation incorporated in Multiplication And Accumulation(MAC) to reduce the memory size. For optimizing memory and data path circuit, the quantized 8bit integer weights are used instead of 32bit floating-point weights for pre-training of MNIST data set. To reduce chip area, the proposed CNN model is reduced by a convolutional layer, a 4*4 Max Pooling, and two fully connected layers. And all the operations use specific MAC with approximation adders and multipliers. 94% of internal memory size reduction is achieved by simultaneously performing the convolution and the pooling operation in the proposed architecture. The proposed accelerator chip is designed by using TSMC65nmGP CMOS process. That has about half size of our previous paper, 0.8*0.9 = 0.72mm². The presented CNN accelerator chip achieves 94% accuracy and 77us inference time per an MNIST image.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.41 no.4
• /
• pp.9-21
• /
• 2018

In South Korea, Jeju Island has a role as a test bed for electric vehicles (EVs). All conventional cars on the island are supposed to be replaced with EVs by 2030. Accordingly, how to effectively set up EV charging stations (EVCSs) that can charge EVs is an urgent research issue. In this paper, we present a case study on planning the locations of EVCS for Jeju Island, South Korea. The objective is to determine where EVCSs to be installed so as to balance the load of EVCSs while satisfying demands. For a public service with EVCSs by some government or non-profit organization, load balancing between EVCS locations may be one of major measures to evaluate or publicize the associated service network. Nevertheless, this measure has not been receiving much attention in the related literature. Thus, we consider the measure as a constraint and an objective in a mixed integer programming model. The model also considers the maximum allowed distance that drivers would detour to recharge their EV instead of using the shortest path to their destination. To solve the problem effectively, we develop a heuristic algorithm. With the proposed heuristic algorithm, a variety of numerical analysis is conducted to identify effects of the maximum allowed detour distance and the tightness of budget for installing EVCSs. From the analysis, we discuss the effects and draw practical implications.