• 디지털융복합연구
• /
• 제12권3호
• /
• pp.249-254
• /
• 2014

무선 랜 시스템은 고속의 데이터를 전송하기 위하여 끊임없이 진화 중이며 통신성능을 향상시키기 위해서는 더욱 정밀한 채널추정이 필수적으로 요구된다. 본 논문에서는 IEEE 802.11 기반 무선 모뎀의 PLCP 구조에서 기존의 긴 훈련심볼만을 이용하여 채널을 추정하는 LS 알고리즘의 성능을 개선하고자 하였다. 48개의 부반송파 중에서 12개의 위치에 짧은 훈련 심볼을 전송하고 있다는 사실을 이용하여 2개의 긴 훈련심볼 뿐만 아니라 하나의 짧은심볼도 함께 사용하여 채널을 추정하는 새로운 LS 추정 알고리즘을 제안하였다. 두 개의 긴 훈련심볼 뿐만 아니라 짧은 훈련 심볼을 이용함으로써 보다 향상된 채널 추정을 제공할 수 있음을 보였으며 제안된 채널 추정알고리즘은 IEEE 802.11p WAVE 차량통신 시스템에도 적용이 가능하리라 생각된다. 또한 학부 및 대학원의 OFDM 관련 채널 추정 교육 시 본 논문의 내용이 유용하게 사용될 수 있을 것이다.

• 한국기계가공학회지
• /
• 제10권6호
• /
• pp.128-133
• /
• 2011

In this study, the steel material for shipbuilding(LR-A class) was used, and FCAW was taken advantage of 3G attitude and they are welded by different welding ways. As a result of analyzing wave with welding monitoring system, the stable values are obtained which are the first floor(electronic current 164~182 A, voltage 24 V), the second floor(electronic current 174~190 A, voltage 22~25 V), the third floor(electronic current 158~188 A, voltage 22~25 V), and fourth floor(electronic current 172~184 A, voltage 22~25 V), at this time, the stable wave standard deviation and changing coefficient could be obtained. When the welding testing through nondestructive inspection was analyzed know defect of welding, there was no defect of welding in A, D, E, but some porosities in B, and slag conclusion near the surface in C, because the length of arc was not accurate, and the electronic current and voltage was not stable. After observing the change of heat affect zone through micro testing, each organization of floor formed as Grain Refinement, so welding part was fine, the distance of heat affect zone is getting wider up to change the values of the electronic current and voltage. As a result of degree of hardness testing, the hardness orders were the heat affect zone(HAZ), Welding Zone(WZ), and Base Metal(BM). When the distribution of degree of hardness is observed. B is the highest degree of hardness The reason why heat effect zone is higher than welding zone and base metal, welding zone is boiled over melting point($1539^{\circ}C$) and it starts to melt after the result of analysis through metal microscope, so we can know that delicate tissue is created at the welding zone. Therefore, in order to get the optimal conditions of the welding, the proper current of the welding and voltage is needed. Furthermore the precise work of welding is required.

• 한국실내디자인학회논문집
• /
• 제25권2호
• /
• pp.30-40
• /
• 2016

This study analyzed the attention concentration tendencies of one(1) subject who showed convergent exploratory acts actively through the gaze-brainwave measurement experiment of cafe space images and our research findings are as follows. First, the areas of interest (AOIs) that the subject gazed visually by paying attention to it and concentrating on it at a cafe space include counter&menu area, sign area, partition area, image wall area, stairs area, and movable furniture area, and built-in furniture area: seven areas in total. Second, conscious gaze frequency appeared the highest in counter&menu area, and conscious gaze appeared more later than in initial times. Third, conscious gaze pattern was divided into the zone that explored various areas dispersely (distributed exploratory zone) and the zone that explored between particular areas concentratedly (intensive exploratory zone). Fourth, as a result of analyzing the brainwave attention concentration, it was found that the attention concentration in prefrontal lobe (Fp1, Fp2) and frontal lobe (F3, F4) rose to a higher level in the zone of 15 to 16 seconds and this time zone was considered to be a zone where gazing at counter&menu area was very active. In addition, the attention concentration appeared higher in the initial zone than in the later zone, among the entire experimental time zones. Finally, as a result of analyzing the changes in activation by brain portion of the SMR wave expressed when maintaining the arousal and attention concentration, it was found that the right prefrontal lobe and the frontal lobe became activated in the time zone when the intensive exploration of "counter&menu area" and "movable furniture${\leftrightarrow}$built-in furniture area" had occurred and the time zone when the intensive exploration of "image wall${\leftrightarrow}$partition area" and "counter&menu${\leftrightarrow}$sign area" had occurred.

• 한국지진공학회논문집
• /
• 제11권4호
• /
• pp.25-31
• /
• 2007

For areas such as the Korean Peninsula, which have moderate seismic activity but no available records of strong ground motion, synthetic seismograms can be used to evaluate ground motion without waiting for a strong earthquake. Such seismograms represent the estimated ground motions expected from a set of possible earthquake scenarios. Local site effects are especially important in assessing the seismic hazard and possible ground motion scenarios for a specific fault. The earthquake source and rupture dynamics can be described as a two-step process of rupture initiation and front propagation controlled by a frictional sliding mechanism. The seismic wavefield propagates through heterogeneous geological media and finally undergoes near-surface modulations such as amplification or deamplification. This is a complex system in which various scales of physical phenomena are integrated. A unified approach incorporates multi-scale problems of dynamic rupture, radiated wave propagation, and site effects into an all-in-one model using a three-dimensional, fourth-order, staggered-grid, finite-difference method. The method explains strong ground motions as products of complex systems that can be modified according to a variety of fine-scale rupture scenarios and friction models. A series of such deterministic earthquake scenarios can shed light on the kind of damage that would result and where it would be located.

• 한국보육지원학회지
• /
• 제12권6호
• /
• pp.249-270
• /
• 2016

The purpose of this study was to investigate the stability and reciprocal effects of maternal parenting stress and perceived social support in early childhood. Specifically, we compared these relations for working and nonworking mothers. The second through fourth wave data of the Panel Study of Korean Children (PSKC) were used in this study. Data were analyzed using t-tests, correlations, and autoregressive cross-lagged modeling analyses. First, parenting stress of non-working mothers was higher than that of working mothers and working mothers perceived higher levels of social support compared to nonworking mothers. Second, both maternal parenting stress and social support were stable over time. Third, there were significant reciprocal effects between maternal parenting stress and perceived social support. Differences between working and non-working mothers were found in the paths from parenting stress to social support. The implications of the stability and reciprocal effects of parenting stress and perceived social support and the difference between working and non-working mothers in the relationship of the two constructs have been discussed.

• 가정과삶의질연구
• /
• 제33권6호
• /
• pp.1-14
• /
• 2015

The purpose of this study was to explore structural relationships among social support, parenting stress, self-perception and parenting behavior perceived by mother and provide preliminary data useful for desirable parenting behavior. For this purpose, the data of fourth wave Panel Study on Korean Children(PSKC) including social support, parenting stress, self-perception and parenting behavior measured by 1,746 mothers with 3-year-old children were analyzed. We identified structural relationships among the variables using SPSS 18.0 and AMOS 18.0 applying structural equation modeling. Measurement model and structure model had favorable goodness of fit and the results of structure models on each path were as follows. First, parenting behavior had positive correlations with social support and self-perception but there was a negative correlation between parenting behavior and parenting stress. Second, the relationship between social support and self-perception was mediated by parenting stress and parenting stress and self-perception mediated the relationship between social support and parenting relationship. In conclusion it is required to raise awareness about the importance of development of various parent education programs and parenting behavior.

• 한국학교보건학회지
• /
• 제29권2호
• /
• pp.63-70
• /
• 2016

Purpose: The purpose of this study was to find the factors influencing adolescents' adult media engagement. The study is based on Agnew's General Strain Theory (GST) and a micro-systemic perspective. Methods: The study examined 479 middle school freshmen who participated in the fourth wave of the Korean Children & Youth Panel Survey (KCYPS) conducted by National Youth Policy Institute. Data were analyzed through descriptive statistics, factor analysis, and reliability analysis using SPSS 22.0 Ver. Also, hypothesis testing was performed via covariance-based structure equation modeling (CB-SEM) using Amos 21.0 Ver. Results: Strain factors had positive effects on adolescent depression, and depression had a positive effect on adult media engagement. Also, cell-phone dependency had a positive mediation effect between depression and adult media engagement. Conclusion: The study's result identified the factors affecting adult media engagement. Therefore, we suggest intervention programs considering adolescents' strains, depression and cell-phone dependency to improve their health.

• 디지털융복합연구
• /
• 제6권2호
• /
• pp.33-40
• /
• 2008

Alvin Toffler는 인류 발전 과정을 세 가지 변화의 물결, 즉 유목 채집 사회에서 농경 사회로의 변화, 산업혁명에 의한 농경 사회에서 산업 사회로의 변화, 그리고 1950년대부터의 후기 산업화 사회로의 변혁으로, 산업 사회에서 정보 사회로의 변혁이 일어나기 시작했으며 탈대량화, 다양화, 지식기반 생산과 변화의 가속이 시작된 시기였다. Herman Maynard와 Susan Mehrtens는 ICT (Information Communication Technology: 휴대폰 등), 인터넷의 발달로 제4의 물결이 시작되고 있다고 주장한다. 이전의 사회 변혁들은 물질 생산이 따르는 가시적인 변혁들이었으나, 디지털 혁명은 시민사회의 참여 확대를 통한 민주주의의 진화된 형태를 가능하게 하고 있다. 지금 우리가 경험하고 있는 제4의 물결의 시작은, 시민사회의 정책 참여와 견제가 효과적이고 효율적으로 이루어지기 시작하는 초고도 정보화 사회의 시작을 의미하며, 정책 결정 자들은 정책 결정 과정에서 그들이 보유하던 절대 영향력의 일부분을 시민사회에 이양됨을 막을 수 없을 것이다. 이러한 대변혁의 시대에 관료주의, Digital Divide, 그리고 시민 참여와의 상관관계를 이해하는 것은 매우 중요하다. 본 논문에서는 시민 참여에 대한 관료주의의 방침과 태도, 제4의 물결의 정책 민주화와 Digital Divide로의 영향 분석을 통하여 정책 결정 자들과 그들의 환경으로의 파급 효과를 논증한다. 본 연구는 이러한 분석과 논증을 통하여, 정책조직들과 시민사회와의 신세기의 바람직한 동반자적 입지 구축에 기여 할 것이다.

• 한국산업융합학회 논문집
• /
• 제23권3호
• /
• pp.453-461
• /
• 2020

In this study, we conducted technology monitoring to search for the current technology level and new technologies targeting the core technologies selected as "convergence technologies based on advanced ICT". This technology group, selected by the National Research Foundation(NRF) as one of the future-emerging technologies in 2018, consists of 'next-generation millimeter wave wireless communication technology', 'data-centric computing technology', and 'immersive media interface' that can be seen as important technologies in the fourth industrial revolution. It is possible to provide strategic research direction to the R&D-related stakeholders of countries or enterprises by providing information on newly emerged technologies through quantitative analysis based on patent data on these technologies. Therefore, in this study, we proposed a new technology for the convergence technologies based on advaned ICT group through patent data based on the newly emerged IPC code, and also suggested that it can suggest a strategic direction in planning R&D on related technologies.

• 한국지진공학회논문집
• /
• 제20권3호
• /
• pp.171-180
• /
• 2016

Earthquake event keeps increasing every year, and the recent cases of earthquake hazards invoke the necessity of seismic study in Korea, as geotechnical earthquake hazards, such as strong ground motion, liquefaction and landslides, are a significant threat to structures in industrial hub areas including coastal facilities. In this study, systemized framework of integrated assessment of earthquake-induced geotechnical hazard was established using advanced geospatial database. And a visible simulation of the framework was specifically conducted at two coastal facility areas in Incheon. First, the geospatial-grid information in the 3D domain were constructed with geostatistical interpolation method composed of multiple geospatial coverage mapping and 3D integration of geo-layer construction considering spatial outliers and geotechnical uncertainty. Second, the behavior of site-specific seismic responses were assessed by incorporating the depth to bedrock, mean shear wave velocity of the upper 30 m, and characteristic site period based on the geospatial-grid. Third, the normalized correlations between rock-outcrop accelerations and the maximum accelerations of each grid were determined considering the site-specific seismic response characteristics. Fourth, the potential damage due to liquefaction was estimated by combining the geospatial-grid and accelerations correlation grid based on the simplified liquefaction potential index evaluation method.