• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.32-39
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• 2009

Compressed Sensing is a method to sample analog signals at a rate under the Nyquist rate. With this scheme, it is possible to represent signals with a relatively smaller number of measurements than that of the conventional sampling method, and the original signals are reconstructed with high probability from the acquired measurements using the linear programming. Compressed sensing allows measurement time and/or the amount of ADC (analog-to-digital converter) resources for the signal acquisitions to be reduced. In this paper, we presents the backgrounds of the compressed sensing, a way to acquire measurements from an analog signal with a random basis, and the signal recovery method. Also we introduce applications of compressed sensing in wireless communications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.611-619
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• 2016

Success in modern war depends on electronic warfare. Therefore, It is very important to identify the kind of Radar PRI modulations in a lot of Radar electromagnetic waves. In this paper, I propose an algorithm to identify Linear up Sliding PRI, Non-Linear up Sliding PRI and Linear Down Sliding PRI, Non-Linear Down Sliding PRI among many Radar pulses. We applied not only the TDOA(Time Difference Of Arrival) concept of Radar pulse signals incoming to antennas but also a rising and falling curve characteristics of those PRI's. After making a program by such algorithm, we input each 40 data to those PRI's identification programs and as a result, those programs fully processed the data in according to expectations. In the future, those programs can be applied to the ESM, ELINT system.

• Archives of design research
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• v.17 no.4
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• pp.37-50
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• 2004

As web-based programming tools(such as flash action script, javascript, java and etc.) has been improved and it has become more aware to take interactivity importantly as users' whole experience, web sites have evolved from the form of webzine to the form of interactive application that displays more interactive interface and gives instant feedbacks for the users' inputs. Web, rather than software, is used to execute relatively easy tasks by users of various levels, so that web sites could give more fun and less cognitive burden by supporting users' tasks in more interactive way. This paper examined design strategies to make more interactive web by figuring out definition of web interaction as users' experience and by analyzing web interaction design trends from cases of interactive web sites. The ultimate objective of this paper is show how design strategies can be adapted in the web interaction design process. Thus, case study of designing interactive bookshell in E-book site was done and is demonstrating one way of adapting strategies to design web interaction.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2
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• pp.426-436
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• 2000

Given a linear arrangement of n base stations which generate multiple types of traffic among themselves, we consider the problem of finding a set of disjoint clusters to cover n base statons so that a cluster is assigned a location server. Our goal is to minimize the total communication cost for the entire network where the cost of intra-cluster communication is usually lower than that of intercluster communication for each type of traffic. The optimization problem is transformed into an equivavalent problem using the concept of relative cost, which generates the difference of communication costs between intracluster and intercluster communications. Using the relative cost matrix, an efficient algorithm of O($mm^2$), where m is the number of clusters in a partition, is designed by dynamic programming. The algorithm also finds all thevalid partitions in the same polynomial time, given the size constraint on a cluster, and the total allowable communication cost for the entire network.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5849-5855
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• 2011

As application development environment changes rapidly, importance of user interface design is increasing. Usually, most of designers are clustering by subjective method of individual to define objects that have relativity in design interface. But, interface which is designed without particular rules just adds inefficiency and complexity of business to user who use this system. Therefore, in this paper, we propose an object oriented design model that allows for flexible development by formalizing the user interface prototype in any GUI environment. The visual cohesion of the user interface is a new set of criteria which has been studied in relation to the user interface contents, and is founded on the basis of the cohesion of the interface as defined using basic software engineering concepts. The visual cohesion includes the issue of how each unit is arranged and grouped, as well as the cohesion of the business events which appear in the programming unit. The interface will become easier to understand and use if the business events are grouped by their inter-relevance within the user interface.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.978-980
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• 2006

A Next Generation Network (NGN) is a packet-based network able to provide services including Telecommunication Services and able to make use of multiple broadband, QoS-enabled transport technologies and in which service-related functions are independent from underlying transport-related technologies. It offers unrestricted access by users to different service providers. It supports generalized mobility which will allow consistent and ubiquitous provision of services to users In this paper, we explain the trend of standardization activity related with open services in ITU-T SG13(Study Group 13). ITU-T SG13 is responsible for studies .elating to the architecture, evolution and convergence of next generation networks including frameworks and functional architectures, signalling requirements for NGN.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1549-1555
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• 2009

The Relay node placement problem is one of the most important requirements for many wireless sensor networks because the lifetime of sensor networks is closely related with the placement of relay nodes which receive sensed data from sensor nodes and forward them to the base station. Relay node placement problem has focused at minimization of dissipated total energy of the sensor nodes in whole networks. However, minimum total energy causes the unbalance of consumed energy in sensor nodes due to different distances between relay nodes and sensor nodes. This paper proposes the concept of energy balance ratio and finds the locations of relay nodes using objective functions which maximize the energy balance ratio. Maximizing this ratio results in maximizing the network lifetime by minimizing the energy consumption of large-scale sensor networks. However, finding a solution to relay node placement problem is NP-hard and it is very difficult to get exact solutions. Therefore, we get approximate solutions to EBR-RNP problem which considers both energy balance ratio and relay node placement using constraint programming.

• The Transactions of the Korea Information Processing Society
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• v.6 no.12
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• pp.3577-3588
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• 1999

This paper describes design and implementation of a general purpose cyber educational system. In this system, there are different types of menus and services according to such user's rights as system operators, professors, assistant instructors, students. In order to keep in close contact between students and professors, provided are various services such as the official announcement, transcripts of lecture, bulletin board, Q/A corner, report box, archive of study materials, electronic mail box, memorandum including checking of one's attendance and school record. For the purpose of activating small group studies and discussion about given subject, it can organize into groups automatically and provide with debating rooms. The system is implemented by separating with both HTML design and programming part by templete concept. Overload of iterative server is solved by adjusting the numbers of DB servers of each service.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.7
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• pp.1400-1406
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• 2007

The core part of education program of the gifted students in information is the thinking ability extension of the programming. We propose four phases of the education model : (1) problem understanding (2) visualization (3) symbolization (4) algorithmization. This model of four phases is applied to learn the abstract concept of recursion using the data structure of Tree. This model is verified by presenting the example of 'Hanoi Tower' to stimulate intellectual curiosity of the students and help to expand their thinking strength. Also, we show the characteristics of which the teaching subjects and learning activities have, by presenting and clarifying the type of education program, properties of the learning contents, and lower level components. The students can deepen and foster the growth of the learning contents by the students' activities of self-evaluation, and their thinking abilities are increased by the guidances of their teachers.

• KNOM Review
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• v.22 no.3
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• pp.1-12
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• 2019

Recently, researching using big data and AI has emerged as a major issue in the ICT field. But, the size of big data for research is growing exponentially. In addition, users of data transmission of existing network method suggest that the problem the time taken to send and receive big data is slower than the time to copy and send the hard disk. Accordingly, researchers require dynamic and flexible network technology that can transmit data at high speed and accommodate various network structures. SDN/NFV technologies can be programming a network to provide a network suitable for the needs of users. It can easily solve the network's flexibility and security problems. Also, the problem with performing AI is that centralized data processing cannot guarantee real-time, and network delay occur when traffic increases. In order to solve this problem, the edge-computing technology, should be used which has moved away from the centralized method. In this paper, we investigate the concept and research trend of SDN, NFV, and edge-computing technologies, and analyze the trends of data central network technologies used by combining these three technologies.