• Journal of the Korean Society of Clothing and Textiles
• /
• v.23 no.5
• /
• pp.715-725
• /
• 1999

The purpose of this study is to understand the Korean consumers' socially responsible clothing acquisition behavior respond to altruistic and economic incentives toward recycling of clothing and the relations between demographic variables and acquisition behavior. Data were collected from the adult females residing in Seoul. Judgement Sampling were performed twice and total 549 sets of answers were used for final analysis. The results are as follows : First the consumers of favoring altruistic and economic incentive prefer to acquire clothing with free cost and the consumers favoring altruistic incentive tend to acquire clothing through unknown persons,. Second the analysis of relationship between the attitude toward recycling incentives and the demographic variables shows that the consumers with relatively higher education have strong will for recycling by altruistic incentive. Third the analysis of relationship between acquisition behavior and the demographic variables shows that consumers with relatively lower education normally acquire clothing from unknown persons and from acquaintance. In addition married persons tend to acquire clothing at free of cost.

• Journal of KIISE:Software and Applications
• /
• v.26 no.5
• /
• pp.621-638
• /
• 1999

재시작 회복시 수행해야 할 작업략을 줄이기 위하여 주기적으로 수행되는 검사점 중 퍼지 검사점은 정상적인 트랜잭션들의 수행과 병행하여 수행된다. 트랜잭션들과 퍼지 검사점의 수행시, 로그 레코드 기록의 순서화를 위한 로그 래취를 획득한 상태에서 로그 레코드를 기록할수있으며, 트랜잭션 엔트리의 무결성을 보장하기 위한 트랜잭션 래취를 획득한 상태에서 트랜잭션은 로그 레코드의 기록과 관련된 트랜잭션 상태를 변경할수 있으며 검사점 프로세스는 트랜잭션의 상태를 검사할 수 있다. 퍼지 검사점과 트랜잭션들이 수행이 비동기로 수행되는 상황에서 로그래취와 트랜잭션 래취의 획득 및 해제 방법이 적절하지 못한 경우, 퍼지 검사점이 어떤 트랜잭션의 트랜잭션 상태를 검사하기 전에 그 트랜잭션에 의하여 기록된 로그 레코드이지만 그 퍼지 검사점이 그 트랜잭션 상태를 검사할때까지 그 로그 레코드의 기록상황이 그 트랜잭션의 트랜잭션 상태에 반영되지 않은 경우가 발생할수 있다. 이 경우, 기록 상황이 트랜잭션 상태에 반영되지 않은 그 로그 레코드를 그 퍼지 검사점에 대한 그 트랜잭션의 상태미방영 로그 레코드라고 한다. 본 논문은 상태미반영 로그 레코드를 발생시키는 상황들을 분석하고, 상태미반영 로그 레코드의 발생에 따른 문제점들을 기술하며, 상태미반영 로그 레코드의 발생에 대하여 전면 방지 기법, 일부 방지 기법 그리고 전면 허용하지만 회복시 이를 해결하는 기법등 세가지 해결책을 제시한다.

• Journal of The Korean Association For Science Education
• /
• v.38 no.3
• /
• pp.407-417
• /
• 2018

The purpose of this study is to analyze the roles of classroom activities in science lessons and student learning motivation in achieving students' scientific competencies, and to suggest implications for science lessons to develop scientific competencies. For this, based on the PISA 2015 data of Korean high school students, we analyzed how classroom activities in science influenced students' scientific competencies through learning motivation variables. As a result of the path analysis, the activities emphasizing interaction and a link to real life predicted intrinsic motivation, instrumental motivation, and science efficacy significantly. On the other hand, the activities that emphasize the student-led inquiry process did not show any effect on learning motivation. In addition, the higher the motivation to learn the science, the higher their scores in three scientific competencies: explaining phenomenon scientifically, evaluating and designing scientific inquiry, and interpreting data and evidence scientifically. The practices of school science lessons indirectly influenced the achievement of scientific competence through learning motivation. Specifically, the activities emphasizing interaction influenced achieving scientific competencies through intrinsic motivation, and the activities emphasizing linkage to real life influenced it through all learning motivation variables. Finally, we discussed some implications for the roles and practices of school science class for enhancing students' scientific competencies.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.17 no.1
• /
• pp.38-46
• /
• 1992

In this thesis, a high speed code synchronization circuit is implemented, which is applicable to frequency hopping FSK tranceiver within 68-88 MIBz band- width. synchronization Process consists of two steps, initial synchronization and tracking. A modified matched filter method using two channel passive correlators matched with short hopping frequencies, synchronization prcfix. is proposed for initial synchronization. To increase probability of initial synchronization, prefix are transmitted repeatedly. The outputs of correlators are sent to synchronization decision circuit, and code start time Is extracted by synchronizatlon decision circuit-Modified matched fitter method makes it possible to reduce complexity in hardware and obtain code acquisition rapidly.Clock recovery circuit regenerates PN code clock for tracking.

• Journal of Advanced Navigation Technology
• /
• v.24 no.4
• /
• pp.285-290
• /
• 2020

This paper presents a time synchronization algorithm based on PLL for application to telemetry systems and implement FPGA logic. The large aircraft of the telemetry system acquires status information through each distributed acquisition devices and analyzes the flight status in real time. For this reason, time synchronization between systems is important to improve precision. This paper presents a PLL based time synchronization algorithm that is less complex than other time synchronization methods and takes less time to process data because there is minimized message transmission for synchronization. The validity of proposed algorithm is proved by simulation of Python. And the VHDL logic was implemented in FPGA to check the time synchronization performance.

• Journal of Digital Convergence
• /
• v.10 no.11
• /
• pp.253-260
• /
• 2012

This study were investigated to the factors affecting smart phone applications to avoid display ads. The results of this study are as follows. First, factor analysis, propensity for advertising intrusion was the result of a single factor. Also showed significant effect advertising intrusion ad avoidance tendency. Second, the smartphone motivation for the use of the results of factor analysis, seven factors were, Entertainment, information acquisition, learning/work use, multimedia use, ease of life, time leverage, respectively. Showed low levels of advertising avoidance learning/working synchronous usability and ease high motivation life. Finally a smart phone for involvement that there is no significant difference in advertising intrusion tendency appeared. High involvement group was obtaining information, entertainment, social relationships, and multimedia use, ease of living, time management motivation significantly higher than the low involvement group. The results of this study it is expected that the smartphone application smartphone users to reduce evasion of advertising practitioners to give answers to create display ads advertising.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.2A
• /
• pp.139-147
• /
• 2008

DVB-S2 (Digital Video Broadcasting-Satellite, Version 2) system transmits frames which adapt their structures based on the channel conditions, thus requiring simultaneous detection of the start of the Same (SoF) and the frame structure at the initial acquisition stage of the receiver. Also, a very low value of the minimum operating signal-to-noise ratio (SNR) for the acquisition necessitates a method utilizing multiple received frames to meet the required performance. In this paper, performance of joint time synchronization and frame structure detection methods using multiple DVB-S2 frames is evaluated by deriving the detection error probability. In particular, we evaluate the performance and complexity variations when the soft- and hard-decision values of the signal correlation output are used, present the synchronization parameters to optimize the performance, and verify the analysis results via computer simulations.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.5C
• /
• pp.479-486
• /
• 2010

In this paper, we propose a novel low-complexity Alamouti coded orthogonal frequency division multiplexing (OFDM) scheme for asynchronous cooperative communications. Exploiting the combination of OFDM symbols at the source node and simple operations including sign change and complex product at the relay node, the proposed scheme can achieve cooperative diversity gain without use of time-reversion and shifting operations that the conventional scheme proposed by Li and Xia needs. In addition, by using the cyclic prefix (CP) removal and insertion operations at the relay node, the proposed scheme does not suffer from a considerable degradation of bit-error-rate (BER) performance even though perfect timing synchronization is not achieved at the relay node. From the simulation results, it is demonstrated that the BER performance of the proposed scheme is much superior to that of the conventional scheme in the presence of timing synchronization error at the relay node. It is also shown that the proposed scheme obtains two times higher diversity gain compared with the conventional scheme at the cost of half reduction in transmission efficiency.

• Journal of the Institute of Convergence Signal Processing
• /
• v.2 no.3
• /
• pp.39-44
• /
• 2001

In frequency hopping spread spectrum(FHSS) communication systems, exact frequency synchronization is required due to the random hopping of carrier frequencies between transmitter and receiver even under harsh channel conditions. For synchronization of FHSS communications, multi-frequency hopping synchronization(MFHS) method has been used in which a small set of frequencies are repeatedly sent several times for long duration. But this long duration resulted in being easily detected by the unauthorized users as well as long duration of acquisition time. In this paper, motivated by these problems, an adaptive synchronization method(ASM) is proposed. ASM is technics to reduce the synchronization time where the number of synchronization frequencies and repetition numbers is adaptively changed (increased or decreased) according to the channel conditions. The performance analysis showed that the time duration of synchronization was reduced to 0.2sec, and the influence of jamming or interference was decreased to 46% in ASM.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.4B
• /
• pp.670-676
• /
• 2010

A time synchronization method for Advanced T-DMB is proposed using PN sequence inserted in PRS for the transmission of hierarchical modulation mode information. The time synchronization offset is estimated through the cross-correlation of the PN sequence and the received PRS. The performance of the proposed method is analyzed by the BER analysis in mobile channel and the results are shown.