• Journal of the Ergonomics Society of Korea
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• v.26 no.4
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• pp.65-73
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• 2007

This study evaluated the short message service (SMS) and multimedia message service (MMS) usability of mobile phones and wireless internet services by performance failure rates and flowcharts that adopted the concept of state diagrams. Forty-eight participants who had an experience of using mobile phones were recruited by posting an advertisement on websites for the experiment. They carried out both SMS and MMS tasks with the mobile phones of LG Cyon and Samsung Anycall as well as the wireless internet services of LGT ez-i, KTF magicN, and SKT NATE. In general, Cyon had the lower performance failure rate than Anycall for SMS, and ez-i had the lowest performance failure rate than the other services for MMS. More specifically through the workflow analysis, most participants used hot keys to take 7-8 steps to send a SMS including a symbol and had a difficulty in typing the symbol. They also took 10-11 steps to send a MMS after taking and attaching two pictures. Anycall, magicN, and NATE had significantly large error and failure rates due to the limited option of the menu paths that users could take and poor compatibilities of menu names and between menu and navigation keys. This study showed the possibility of use of flowcharts for systematic and specific usability evaluation methods and found the causes of performance errors and failures with mobile phones and wireless internet services to provide insight into their design.

• Journal of the Korean Society of Costume
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• v.51 no.5
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• pp.157-173
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• 2001

In fashion, there are various cultural aspects that exist in complexity, where according to the era, even fashion items newly develop and prevail into various designs in the organic function with reality of related cultural phenomenon and aesthetic aim. Among the fashion items, the shoe is historically considered as the shield from lust and also the provision of praise against the most emotional incitement. Mankind has started wearing shoes out of the functional purpose of protection since the ancient Egyptian times. Thereafter humankind has been creating shoes artistically in respect to shape, color, and quality of material, etc, as an expression of aesthetical awareness and introspective desire for beauty. As modern fashion increasingly regards the total fashion image much more important than each items consisting the whole outfit, the role of shoe became essential more than ever. Contrary to its relative importance, little academic attention was given to this area yet, while prestigious museums and galleries in Europe and the USA have held exhibitions of shoes in view of both historical and artistic aspects. This study aims to make a historical inquiry of western shoes. through which their aesthetic values can be drawn. Literature on this subject including aesthetics, history of costume and arts were referred. Fashion magazines and catalogues were investigated for additional information. The process and results of this study are meant to be a suggestion not only to further studies but also to artistic and creative shoe design. Originated for the functional purpose, shoes have evolved in various shapes with different meanings attached to it. When the technological development made the satisfaction for functional needs possible, the intrinsic attribute, the aesthetic value was pursued. The historical contemplations of shoes from Egyptian times to the 1990's led to the results that the intrinsic aesthetic value of shoes can be summarized as follows: 1) protection and extension of body, 2) need for decoration, 3) erotic expression, 4) symbol of dignity and class, 5) fashion.

• Journal of the Korean Society of Costume
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• v.54 no.6
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• pp.101-117
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• 2004

Opposed to following the contours of the human body, the voluminous enlargement in costume, which characterizes the distinguished enlargement in space rather than the contour of human body, mean the enlargement aspect involving the vertical protrusion and the expansion of shape and volume as well as the extension of length. The costume enlargement as a different method of expression is a symbol showing a meaning of something and an aesthetic expression containing man's will. This voluminous enlargement of costume, as an aesthetic expression, has different formative characteristicsand immanent meanings according to ideals and thoughts as well as social and cultural background of each age Accordingly, the aesthetic consciousness also differaccording to the change of the times. To study the aesthetic consciousness of costume's voluminous enlargement, focous had been given to milieus that show comparatively conspicuous voluminous enlargement Periods that have been subjected to this study include costumes of the ancient Egypt, the Gothic period in the Middle age, the Renaissance, the Baroque Rococo of the recent times, and the modern era (Empire, Romantic, Art Nouveau. etc) With focus given to the principle of design obtained through this study were used to analyze the aesthetic characteristics, Futhermore, based on the spirit of the times and the socio-cultural symbolism, research on immanent meanings, as supported by objectivity and universal validity, was also made, the enlargement beauty of costume had been placed under the aesthetic category and, by interpreting the analogies of presented in aesthetic consciousness, the true nature of the voluminous enlargement in costume had been traced. To Conclude, the aesthetic consciousness of the voluminous enlargement of the costumes in history was found to have following characteristics: (l) Metaphorical (2) Unlooked-for irregularity (3) feeling of satisfaction driven by self-enlargement (4) Dignified sublimity (5) Symbol of wealth and class (6) Ceremonial dignity (7) Tradition of the nobility (8) Aesthetic ornament (9) Ideal contour of the body

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.794-806
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• 2004

This paper deals with correction of frequency offset and analysis of quantization angle noise in the IEEE 802.1la OFDM system. The rotation phase per symbol due to the carrier frequency offset is estimated from auto-correlation of the short Preambles, which are over-sampled for the reduction of noise in OFDM signals. The pilot signals are introduced to estimate the rotation phase per OFDM symbol due to estimation error of the carrier frequency offset and the sampling frequency onset. During the estimation and correction of the frequency onsets, a CORDIC processor and a look-up table are used for the conversion between a rotation phase and its complex number. Being calculated by a limited number of bits in the CORDIC processor and the look-up table, the rotation phase and its complex number have quantization angle errors. The quantization errors are analyzed as SNR (signal to noise ratio) due to the quantization bit numbers. The minimum bit number is suggested to meet the specification of IEEE 802.1la properly. Finally, the quantization errors are evaluated through simulations on number of quantization bits and SNR of received signals.

• Journal of IKEEE
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• v.24 no.3
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• pp.838-844
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• 2020

In this paper, we propose an efficient Viterbi processor using Joint Viterbi detection and decoding (JVDD) algorithm for a for bluetooth low energy (BLE) system. Since the convolutional coded Gaussian minimum-shift keying (GMSK) signal is specified in the BLE 5.0 standard, two Viterbi processors are needed for detection and decoding. However, the proposed JVDD scheme uses only one Viterbi processor by modifying the branch metric with inter-symbol interference information from GMSK modulation; therefore, the hardware complexity can be significantly reduced without performance degradation. Low-latency and low-complexity hardware architecture for the proposed JVDD algorithm was proposed, which makes Viterbi decoding completed within one clock cycle. Viterbi Processor RTL synthesis results on a GF55nm process show that the gate count is 12K and the memory unit and the initial latency is reduced by 33% compared to the modified state exchange (MSE).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1A
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• pp.64-72
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• 2012

We consider multiuser multiple antenna two-way relaying systems in which all users exchange their data with their counterparts with the help of a relay. The systems complete all data exchanges in two time phases called multiple access phase and broadcasting phase for spectral efficiency and therby require an effective scheme reducing self-interference (SI) and multiuser interference (MUI). Different from the conventional scheme suppressing both SI and MUI at the relay, the proposed scheme adopts SI cancelation (SIC) at the users and renders the relay to suppress the MUI mainly considering the SIC output. We analyze the symbol error rate (SER) and the achievable diversity order of the proposed scheme when the multiple access phase is dominant in the performance and obtain simulation results on the SER and the sum rate under various conditions. The results show that the proposed scheme improves the symbol error rate and the sum rate remarkably at the cost of complexity increase.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.295-298
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• 2003

In this paper, a novel maximum a posterion (MAP) estimation for the channel decoding of H.264 codes in the presence of transmission error is presented. Arithmetic codes with a forbidden symbol and trellis search techniques are employed in order to estimate the best transmitted. And, there has been growing interest of communication, the research about transmission of exact data is increasing. Unlike the case of voice transmission, noise has a fatal effect on the image transmission. The reason is that video coding standards have used the variable length coding. So, only one bit error affects the all video data compressed before resynchronization. For reasons of that, channel needs the channel codec, which is robust to channel error. But, usual channel decoder corrects the error only by channel error probability. So, designing source codec and channel codec, Instead of separating them, it is tried to combine them jointly. And many researches used the information of source redundancy In received data. But, these methods do not match to the video coding standards, because video ceding standards use not only one symbol but also many symbols in same data sequence. In this thesis, We try to design combined source-channel codec that is compatible with video coding standards. This MAP decoder is proposed by adding semantic structure and semantic constraint of video coding standards to the method using redundancy of the MAP decoders proposed previously. Then, We get the better performance than usual channel coder's.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.10
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• pp.885-892
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• 2013

The main advantage of ESPAR antenna is that ESPAR antenna requires only a single RF chain for reduction of transceiver's hardware complexity, as compared to conventional MIMO system. In conventional MIMO system, each data symbol is mapped to each antenna. But, each data symbol is mapped to each orthogonal basis pattern in ESPAR antenna system. In this paper, we design beamspace MIMO system using ESPAR antenna with single RF chain for MIMO system of low-complexity and low power consumption. And then, we analyze performance of beamspace MIMO according to each PSK modulation. Performance of beamspace MIMO system is similar to performance of conventional MIMO system. As a result of analyzing the performance of beamspace MIMO system using higher-order PSK modulation. we can confirm that performance characteristic of beamspace MIMO system with low complexity and low power consumption is similar to digital communication of signal domain.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7582-7588
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• 2015

Noncoherent receivers are favored for block-code-modulated ultrawideband impulse radio (UWB-IR) systems because of their low implementation complexity compared with coherent rake receivers. However, existing noncoherent schemes, such as transmitted reference (TR) systems and averaged differential receivers (ADR), suffer from performance degradation and energy efficiency loss. Codeword matching and signal aggregation (CMSA) is a low complexity noncoherent receiver for UWB-IR. As the frame/symbol duration is shortened to boost data rate, interframe interference (IFI) or intersymbol interference (ISI) occurs and degrades the detection performance of CMSA. In this paper, block coded correlator which consists of the delay components and the reference signal is proposed to improve the performance of the receiver. Simulation results show that the proposed system leads to the better performance compared to the conventional CMSA receiver.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2834-2851
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• 1997

In this paper, a design and implementation of VHDL compiler front-end, aims at supporting the full-set of VHDL '87 & '93 LRM and carring out the preprocessing of VHDL-to-C, is described. The VHDL compiler front-end includes 1)the symbol tree of analyzed data to represent the hierarchy, the scope and visibility, the overloading and homograph, the concurrent multiple stacks in VHDL, 2)the data structure and supportig routies to deal with the objects, the type and subtype, the attribute and operation in VHDL, 3)the analysis of the concurrent/sequential statements, the behavior/structural descriptions, of semantic token and the propagation of symbol & type to improve the registration and retrieval procedure of analyzed data. In the experiments with Validation Suite, the VHDL compiler front-end could support the full-set specification of VHDL LRM '87 & '93; and in the experiments to asses the performance of symantic token for the VHDL hierachy/visibility/concurrency/semantic checking, the improvement of about 20-30% could be achieved.