• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.120-130
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• 2009

In this paper, we propose a receiver structure for frequency synchronization in OFDMA (Orthogonal Frequency Division Multiple Access) system which is considered as 3GPP LTE(Long Term Evolution) downlink. In general, OFDMA frequency synchronization consists of two parts: coarse synchronization and fine synchronization. We consider P-SCH (Primary-Synchronization Channel) and CP (Cyclic Prefix) of OFDMA symbol for coarse synchronization and fine synchronization, respectively. The P-SCH signal has two remarkable disadvantages that it does not have sufficiently many sub-carriers and its differential correlation characteristic is not good due to ZC (Zadoff Chu) sequence-specific property. Hence, conventional frequency synchronization algorithms cannot obtain satisfactory performance gain. In this paper, we propose a modified differential correlation algorithm to improve performance of the coarse frequency synchronization. Also, we introduce an effective PLL (Phase Locked Loop) structure to guarantee stable performance of the fine frequency synchronization. Simulation results verify that the proposed algorithm has superior performance to the conventional algorithms and the 2nd-order PLL is effective to track the fine frequency offset even in high mobility.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.804-810
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• 2002

The code division multiple access(CDMA) system capacity is limited by the amount of interference of the system. To reduce the unnecessary interference, this paper proposes optimized cell identification codes for site selection diversity transmission(SSDT) power control in wideband code division multiple access system of third generation partnership project(3GPP). The main objective of SSDT power control is to transmit on the downlink from the primary cell, and thus reducing the interference caused by the multiple transmission. In order to select a primary cell, each cell is assigned a temporary identification(ID) and user equipment(UE) periodically informs a primary cell ID to the connecting cells during soft handover. The non-primary cells selected by UE do not transmit the dedicated physical data channel(DPDCH) to reduce the interference. A major issue with the SSDT technology is the impact of uplink symbol errors on its performance. These errors can corrupt the primary ID code and this may lead to wrong decoding in the base station receivers. The proposed SSDT cell ID codes are designed to minimize the problem and to be easily decoded using simple fast Hadamard transformation(FHT) decoder.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.5
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• pp.122-133
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• 2010

Humans desire the achievement a of sense of unity between themselves and place to create an identity of place as a realization of his or her sense of belonging. Humans develop ideas from their culture and environment to be expressed physically within the landscape through symbols. Symbols are formed within a place through the structure of the space and, more visually, through the details. The purpose of this paper is to examine the structure of space and the details of 'the Courtyard of the lions' in the Alhambra and to study how the details influence the formation of the identity of place. This paper also compares the structure and details in terms of the meaning of symbols, design languages, cultural, social and historical background and the experience of the place. The structure of the space in 'the Courtyard of the Lions' represents Paradise in the Islamic religion a common theme in the composition of traditional Islamic gardens. The design languages expressed within the structure are order, balance, accent and enclosure; the inherit meanings of the structure are religion, the natural environment and way of life. The details tell of the ideology of Paradise, royalty, nature, and praise of God, while their design languages include physical and visual continuity, accent, variation, the feeling of movement, rhythm, and depth perception. The details also express the historical background of the Dynasty of Nasrid and the style of Mudejar. The name 'the Courtyard of the Lions' was taken from the detail of the lim figures, details within the landscape which are important in building an identity of place. This study demonstrates that the details at 'the Courtyard of the lions' achieved a sense of unity between man and place. In conclusion, details have immense influence in building of the identity of place.

• Journal of Navigation and Port Research
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• v.39 no.4
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• pp.293-297
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• 2015

Underwater acoustic communications has been limited use for military purposes in the past. However, the fields of underwater applications expend to detection, submarine and communication in recent. The excessive multipath encountered in underwater acoustic communication channel is creating inter symbol interference, which is limiting factor to achieve a high data rate and bit error rate performance. To improve the performance of a received signal in underwater communication, many researchers have been studied for channel coding scheme with excellent performance at low SNR. In this paper, we applied BCJR decoder based ( 2,1,7 ) convolution codes and to compensate for the distorted data induced by the multipath, we applying the turbo equalization method. Through the underwater experiment on the Gyeungcheun lake located in Mungyeng city, we confirmed that turbo equalization structure of BCJR has better performance than hard decision and soft decision of Viterbi decoding. We also confirmed that the error rate of decoder input is less than error rate of $10^{-1}$, all the data is decoded. We achieved sucess rate of 83% through the experiment.

• Journal of the Korean association of regional geographers
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• v.18 no.3
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• pp.310-325
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• 2012

Human being has used place names to differentiate one place from another. Place names are the products of collective human cognition in that a place name is chosen when it successfully represents the identity of a place. In addition, place names have been changed by the competition and struggle between social agencies and the political imperatives of hegemonic groups to impose their identity on the places. Recent geographic studies on place names have focused on the social and political processes behind the change of place names. In this vein, the purpose of this study is investigating the debates on the decision of city names in the process of the administrative reorganization in mid 1990s by the lens of political geography. Residents in cities and counties tried to justify their arguments by emphasizing historical backgrounds and popularity of their names. Additionally, economic power and potential were mobilized for the political resources to win over the battle over city names. The result, however, shows that the decision of newly consolidated cities' name was mainly made by the amount of political resources, such as population and number of seats in local assemblies. Several regions tried to use city names to negotiate with counterparts. In sum, the decision of place names is the product of political competitions, and the place name becomes the symbol of territorial identity. Place names have been in the center of disputes in local politics even after the name was decided, which suggest further studies on reasonable solution to mitigate the disputes to be expected when additional reorganization of administrative districts.

• Science of Emotion and Sensibility
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• v.12 no.2
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• pp.193-204
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• 2009

The importance of corporate identity design has been recently highlighted in the marketing. However, logotype among marks that represent the image of a company has been neglected relatively comparing to symbol mark and logo mark. A logotype should be something to represent the personalities and characteristics of a company in suggestive ways. For such reasons, the image expressions by shape are thought to be important. Consequently, the formative aspects of visual communication design should be examined with emphases. However, it is true that studies on the formative aspects regarding logotypes and logo marks, especially studies on the shapes of font types and the responses of consumers to them, are lacking. Accordingly, this study examined the visual shape of logotype preferred by consumers and the shape of logotype preferred by consumers according to the business type of companies. As a result of research, there were differences in the elements of logotype preferred according to the business type of companies; as for construction companies is preferred the body of the type of dotum font with bold stem, without serif, with oblique, straight-line and curve-line endings; as for banks is preferred the body of the type of dotum font without serif, with oblique ending and with one-side curve style of serif, the stem in a middle level; as for laboratories is preferred the body of the type of dotum font with oblique ending, with bold stem and straight-line serif. The elements that should be commonly applied to construction companies, banks and laboratories appear to be the oblique ending but the curve-line ending and shallow stem seemed to be avoided. On the other hand, the serif, ending and gulim appeared to be applied differently according to the business type.

• School Mathematics
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• v.16 no.4
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• pp.803-825
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• 2014

From the early stages of learning algebra, literal symbols are used to represent algebraic objects such as variables and parameters. The concept of parameters contains both indeterminacy and fixity resulting in confusion and errors in understanding. The purpose of this research is to compare the beginners of algebra and pre-service teachers who completed secondary mathematics education in terms of understanding this paradoxical nature of parameters. We recruited 35 middle school students in eight grade and 73 pre-service teachers enrolled in a undergraduate course at one university. Using them we conducted a survey on the perception of the nature of parameters asking if one considers parameters suggested in a problem as variables or constants. We analyzed the collected data using the mixed method of qualitative and quantitative approaches. From the analysis results, we identified several difficulties in understanding of parameters from both groups. Especially, our statistical analysis revealed that the proportions of subjects with limited understanding of the concept of parameters do not differ much in two groups. This suggests that learning algebra in secondary mathematics education does not improve the understanding of the nature of parameters significantly.

• Archives of design research
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• v.17 no.1
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• pp.319-328
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• 2004

The communication environment made by digital technologies has made it possible to exchange information and deliver messages fast and easily among people of various classes in virtual space beyond time and space. Net-generation, who is accustomed to this virtual space, couldn't be satisfied with the linear text-oriented language any more, and began to make signs by use of computers in order to differentiate itself from others and to express its desires. Among the signs, emoticon created by joint of popular culture and digital communication centering around young generation is a new visual sign and emotional sign that can deliver a sender's feelings contained in a message. This paper has studied social phenomena, their relationships with emoticon and background of its creation through documentary review of media development, changes in the communication environment and popular culture. Furthermore, it has analyzed the meaningful action and roles of emoticon as a sign in terms of semiotics and also, studied a possibility of using emoticon as a new emotional sign. The study results say that emoticon can play the roles of a non-linguistic sign just like general signs that make mutual exchange through meaningful action, and also that it can be used to effectively deliver messages not only in virtual space, but also in advertising, posters, magazines and CI. However, emoticon is better at emotional expressions yet than other textual signs or visual signs, but in order to position itself as a universal and popular sign, emotional expressions should be clear, any difference in understanding messages should be removed, and message delivery should be more efficient.

• Archives of design research
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• v.17 no.3
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• pp.209-220
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• 2004

Folk painting was prevalent among working classes in the cultural territory of chinese characters including Korea, Japan, and Vietnam. Other than Gilsangmunja-do(lucky and vulgar illustrated Chinese Character), the most popular of its kind, there are various types of different Munja-do(illustrated Chinese Character) which is more shaped/modeled. Chinese Nianhua style was popular in various parts of China from late Ming Dynasty to early Qing Dynasty, and they were conveyed to neighboring countries after the 17th century, where they adopted unique tradition of each country. Acquiring theme from Chinese characters, these Chinese Nianhua or Munja-do are designed by making images into characters or characters into images. They express the invisible 'Cosmological Taoism' as a visible shape and line. This kind of symbol system, using character as a subject matter, can only be witnessed in the cultural territory of chinese characters by the use of ideograms. It is worth of paying attention today because the uniqueness of each country's style reflects diverse life styles of the contemporary civilization. Specifically, values of Munja-do as a traditional culture may not be underestimated in today's society where culture has become the center of concern. Munja-do in Korea should be carefully examined since Korea has had a very unique Munja-do culture that cannot be found from other countries. Therefore, by comparing Munja-do styles of today's the cultural territory of chinese characters countries, we may enlighten ourselves on our tradition and flourish our cultural contents.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.63-75
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• 2010

In this paper, the equalizer techniques that is able to adopt the digital on-channel repeater for 8VSB-based DTV system has been analyzed and we propose an effective equalizer structure which can reduce the error propagation phenomenon by the feedback signal and improve the receiver performance at the same time. In order to confirm the effective cancellation of the feedback signal, the multi-level Correlation LMS scheme is proposed through the analysis of conventional basic LMS based DFE and Correlation LMS algorithm and as compared with the conventional method, we can confirm the reduction of error propagation. When performing the computer simulation, as the Brazil channel model which is very popular for DTV broadcasting system is adopted, the result is drawn by comparing and analysing the equalizer algorithm. We have examine the symbol error rate which is in the range of 15~25dB of operation receipt SNR and MSE(Mean Square Error) in the DTV broadcasting system. As a result of comparing with the existing method, the signal-noise ratio which is necessary for maintain the bit error correction ability that the means of proposal is same is reduced by about 2~5dB, and in the rate of convergence through the MSE, we found the reduction of needed time.