In recent years, advances in the digital and live streaming economy have led to exponential growth in the number of self-employed streamers who have become an integral part of the self-driven digital labor force. However, previous research on the impact of streamers' work time arrangements on their virtual gifts remains scarce. To fill this gap in the literature, using large-scale data from Kuaishou live streaming platform, we demonstrate that several features of streamers' work time have an important impact on their virtual gifts. Specifically, our results suggest that work time duration and timing improve streamers' virtual gifts; meanwhile, work time tempo has an adverse effect on streamers' earnings. Taken together, our results provide novel and actionable insights for millions of self-employed streamers, agencies, platforms, and policymakers.

Spent nuclear fuel (SNF) characterization is important in terms of nuclear safety and safeguards. Regardless of whether SNF is waste or energy resource, the International Atomic Energy Agency (IAEA) Specific Safety Guide-15 states that the storage requirements of SNF comply with IAEA General Safety Requirement Part 5 (GSR Part 5) for predisposal management of radioactive waste. GSR Part 5 requires a classifying and characterizing of radioactive waste at various steps of predisposal management. Accordingly, SNF fuel should be stored/handled as accurately characterized in the storage stage before permanent disposal. Appropriate characterization methods must exist to meet the above requirements. The characterization of SNF is basically performed through destructive analysis/non-destructive analysis in addition to the calculation based on the reactor operation history. Burnup, Initial enrichment, and Cooling time (BIC) are the primary identification targets for SNF fuel characterization, and the analysis mainly uses the correlation identified between the BIC set and the other SNF characteristics (e.g., Burnup - neutron emission rate) for characterizing. So further identification of the correlation among SNF characteristics will be the basis for proposing a new analysis method. Therefore, we aimed to simulate a SNF assembly with varying burnup, initial enrichment, and cooling time, then correlate other SNF properties with BIC sets, and identify correlations available for SNF characterization. In this study, the ‘CE 16×16’ type assembly was simulated using the SCALEORIGAMI code by changing the BIC set, and decay heat, radiation emission characteristics, and nuclide inventory of the assembly were calculated. After that, it was analyzed how these characteristics change according to the change in the BIC set. This study is expected to be the basic data for proposing new method for characterizing the SNF assembly of PWR.

The radioactive waste repository consists of an engineered barrier and a natural barrier and must be managed safely after isolation. We classify the geological events of natural barriers for the evaluation of their present and future disposal stability assessment, they can be divided into regional and regional evolutions according to their scale. Regional evolution can be quantitatively explained by plate tectonics and regional rock distribution, and local evolution can be explained by petrological, mineralogical evidence and ductile, brittle deformation. Plate tectonics can explain the change quantitatively by restoring the direction of the Earth’s magnetic field recorded when rocks were formed. The time units for these changes are tens of millions of years to hundreds of millions of years, but plate tectonic is a way to estimate geological history. It can be assessed by extrapolating past knowledge considering the known geological events of radioactive waste repository. It is possible to derive a conservative value of the change of the geological environment in the time unit of disposal stability. The Korean Peninsula belongs to the edge of the Eurasian plate and is divided into Gyeonggi, Yeongnam Massif, Okcheon orogeny belt, and Gyeongsang Basin. To quantitatively determine their geological history, we collected paleomagnetic data using rocks from the Korea Peninsula (paleomagnetic database and papers). We attempted to carry out the apparent polar wander paths (APWPs) on the Korean Peninsula by collecting and sorting data. Since the Korean Peninsula is composed of multiple massifs, this APWP is expected to serve as a basis for explaining the local crustal rotation or brittle ductile deformation. Furthermore, by extrapolating the change pattern from the past to the present, it can contribute to the estimation of the future geological evolution.

실시간 하이브리드 실험법(real-time hybrid testing method)은 구조물의 수치해석부와 실험부 부분구조를 운동방정식으로 통합하여 실시 간으로 동시에 계산과 실험을 수행하는 방법이다 본 연구는 실시간 하이브리드 실험법을 사용하여 수동 및 준능동 MR감쇠기가 설치된 건축구조물의 내진성능을 정량적으로 평가한다. 건물 모델은 실물 크기 5층 건물을 강제진동실험 결과를 통해 식별한 수치모델로 사용하였고, MR감쇠기는 실험적 부분구조르 UTM에 설치되었다. 본 연구에서 수행되는 실시간 하이브리드 실험은 사인파 및 지진파 가진을 통하여 얻은 결과와 전류에 따른 MR감쇠기의 제어력을 이용하여 얻은 Bouc-Wen모델을 사용하여 얻은 해석모델과 일치함으로 그 유효성을 입증하였다. 또한 예비연구로써 구조물의 응답을 최적으로 제어하기 위한 clipped-optimal 제어알고리즘과 modulated homogeneous friction 준능동 제어알고리즘을 MR감쇠기에 적용하였다. 각 전류별 Bouc-Wen모델을 곡선맞춤하여 각각의 Bouc-Wen모델 파라미터를 식별하였으며 그 결과를 준능동 제어알고리즘 수치해석에 적용하였다. 또한 실시간 하이브리드 실험법을 이용한 준능동 제어 실험결과와 해석결과를 비교하여 준능동 제어알고리즘의 성능을 평가함에 있어 실시간 하이브리드 실험이 합리적임을 보여준다.

자기 유사성(self-similarity)은 다양한 네트워크 환경에서 공통적으로 발생하는 현상인 것으로 정체 제어에서 자기 유사성 트래픽의 장거리 상관 구조를 활용할 가능성과 MTS(Multiple Time Scale) 정체 제어의 프레임워 크를 발전시켜, 이 프레임워크가 전송 율 기반 피드백 제어의 성능을 향상시키는 데 시뮬레이션을 통해 트래 픽 조건으로 다음과 같이 연구한다. 자기유사성 트래픽 조건에서 3가지 단계로 구성한다. 먼저 TCP의 모듈 형 확장에서 Tahoe, Reno, Vegas등 다양한 버전의 TCP에 적용되는 간단한 인터페이스를 통한 함수 호출을 정의하고, 이것이 성능을 크게 향상시는 것을 입증한다. 두 번째로, 광대역 WAN에서 지연-대역폭의 곱이 높을 경우 더욱 심각해지는 사후 제어의 불확실성 차이를 해소함으로써 MTS TCP가 기반 피드백 제어에 사전성 을 부여한다는 것을 입증한다. 세 번째는 트래픽 제어의 3가지 차원인, 즉 추적 능력, 연결 지속 기간, 공정성 이 성능에 미치는 영향 등을 비교 분석하여 입증한다.

제7차 교육과정에 따라서 집필된 지구과학 I, II 교과서와 국내외 각종 지구과학 교재의 지질 연대 자료를 검토하였다. 지구과학 I, II 교과서의 자료는 대부분 최신의 자료가 아니며, 많은 자료들은 지질학 원론과 지구과학 개론 등의 국내 대학 교재에 제시된 수 십년 전의 자료를 그대로 따랐다. 또한 외국 대학의 지구과학 또는 지질학 개론서의 경우에서도 유사하게 수 십년 전의 자료를 제시하고 있다. 최근 국제 층서 위원회(ICS)에 의하여 연구 제시된 국제 층서 챠트(ICS 2000), 국제 지질 연대표(IGTS 2003) 및 지질 연대표(GTS 2004) 등의 많은 새로운 자료들이 제시되어 있다. 새로운 자료 중에서 중요한 것들에는 신생대의 고제3기와 신제3기, 석탄기의 미시시피아세와 펜실베니아세, 원생이언의 고원생대, 중원생대 및 신원생대 그리고 시생이언의 시시생대, 고시생대, 중시생대 및 신시생대를 들 수 있다. 이들 새로운 지질 연대 자료는 새로운 지구과학 교과서 집필시 인용되어야 할 것이다.

Challenging Minisatellite Payload (CHAMP) satellite magnetic data are used to investigate the latitudinal variation of the storm-time meso-scale field-aligned currents by defining a new metric called the FAC range. Three major geomagnetic storm events are considered. Alongside SymH, the possible contributions from solar wind dynamic pressure and interplanetary magnetic field (IMF) BZ are also investigated. The results show that the new metric predicts the latitudinal variation of FACs better than previous studies. As expected, the equatorward expansion and poleward retreat are observed during the storm main phase and recovery phase respectively. The equatorward shift is prominent on the northern duskside, at ~58° coinciding with the minimum SymH and dayside at ~59° compared to dawnside and nightside respectively. The latitudinal shift of FAC range is better correlated to IMF BZ in northern hemisphere dusk-dawn magnetic local time (MLT) sectors than in southern hemisphere. The FAC range latitudinal shifts responds better to dynamic pressure in the duskside northern hemisphere and dawnside southern hemisphere than in southern hemisphere dusk sector and northern hemisphere dawn sector respectively. FAC range exhibits a good correlation with dynamic pressure in the dayside (nightside) southern (northern) hemispheres depicting possible electrodynamic similarity at day-night MLT sectors in the opposite hemispheres.

One of the most frequently performed tasks in human-robot interaction (HRI), intelligent vehicles, and security systems is face related applications such as face recognition, facial expression recognition, driver state monitoring, and gaze estimation. In these applications, accurate head pose estimation is an important issue. However, conventional methods have been lacking in accuracy, robustness or processing speed in practical use. In this paper, we propose a novel method for estimating head pose with a monocular camera. The proposed algorithm is based on a deep neural network for multi-task learning using a small grayscale image. This network jointly detects multi-view faces and estimates head pose in hard environmental conditions such as illumination change and large pose change. The proposed framework quantitatively and qualitatively outperforms the state-of-the-art method with an average head pose mean error of less than 4.5° in real-time.

There have been many suggestions and much debate about climate variability during the Holocene. However, their complex forcing factors and mechanisms have not yet been clearly identified. In this paper, we have examined the Holocene climate cycles and features based on the wavelet analyses of 14C, 10Be, and 18O records. The wavelet results of the 14C and 10Be data show that the cycles of ~2180-2310, ~970, ~500-520, ~350-360, and ~210-220 years are dominant, and the ~1720 and ~1500 year cycles are relatively weak and subdominant. In particular, the ~2180-2310 year periodicity corresponding to the Hallstatt cycle is constantly significant throughout the Holocene, while the ~970 year cycle corresponding to the Eddy cycle is mainly prominent in the early half of the Holocene. In addition, distinctive signals of the ~210-220 year period corresponding to the de Vries cycle appear recurrently in the wavelet distribution of 14C and 10Be, which coincide with the grand solar minima periods. These de Vries cycle events occurred every ~2270 years on average, implying a connection with the Hallstatt cycle. In contrast, the wavelet results of 18O data show that the cycles of ~1900-2000, ~900-1000, and ~550-560 years are dominant, while the ~2750 and ~2500 year cycles are subdominant. The periods of ~2750, ~2500, and ~1900 years being derived from the 18O records of NGRIP, GRIP and GISP2 ice cores, respectively, are rather longer or shorter than the Hallstatt cycle derived from the 14C and 10Be records. The records of these three sites all show the ~900-1000 year periodicity corresponding to the Eddy cycle in the early half of the Holocene.

Smartphones change the picture of data and information sharing and make it possible to share various real-time flooding data and information. The vulnerability indicators of farmland inundation is needed to calculate the risk of farmland flood based on changeable hydro-meteorological data over time with morphologic characteristics of flood-damaged areas. To find related variables show the vulnerability of farmland inundation using the binary-logit model and correlation analysis and to provide vulnerability indicators were estimated by fuzzy set method. The outputs of vulnerability indicators were compared with the results of Monte Carlo simulation (MCS) for verification. From the result vulnerability indicators are applicable to mobile_based information system of farmland inundation.

본 논문에서는 대수-선형 파손율 모형(log-linear ROCOF)과 와이블 파솔율 모형(Weibull ROCOF)을 이용하여 상수도 주철 배수관로의 파손율을 모형화하고, '수정된 시간 척도'를 이용하여 최적교체시기를 산정할 수 있는 방법이 개발되었다. 두 ROCOF의 모형화를 위하여 개별 관로의 파손시간을 기록한 '파손 시간자료(failure-time data)'와 일정 시간간격 사이에서 발생하는 파손횟수를 기록한 '파손 횟수자료(failure-nu

A purpose of developing a sound source tracking system in this paper is to reduce the noise efficiently from the received signal by microphone array and measure the signal's time delay between the microphones. I have applied the wavelet analysis algorithm to the system and calculated the sound source's relative position For the performance evaluation, I have compared with the results of utilizing the digital filtering methods based on the FIR LPF using Kaiser window function and the inverse Chebyshev IIR LPF. As a result, I have confirmed the fact that 'time-scale' filter using inverse discrete wavelet transform was suitable for this system.

입력수문자료의 시간 스케일이 모형의 계산결과에 미치는 영향을 검토하였다. 동일한 강우사상에 대한 각기 다른 시간 스케일의 입력수문자료를 확보하고 이를 TOPMODEL에 적용하였다. 매개변수 보정을 위해 유전자 알고리즘을 사용하였다. 민감도 분석 결과는 상이한 시간 스케일이 TOPMODEL의 운영에 있어서 매개변수 공간에 대한 시각을 제공하였다. 입력수문자료의 시간 스케일의 변화는 모의효율과 평균 지하수위, 총유출량에 대한 지표유출과 지표하유출의 비, 그

The relationship between air temperature and sea surface temperature are studied using the daily air temperature and sea surface temperature data for 25 years (1970∼1994) at 9 coastal stations in Korea. Seasonal variations of air temperature have larger amplitudes than those of sea surface temperature. The seasonal variations of air temperature leads those of sea surface temperature by 2 to 3 weeks. The anomalies of sea surface temperature and air temperature are positively correlated. The long term anomalies of sea surface temperature and air temperature with time scales more than 1 month are more highly correlated than those of short term, with time scales less than 1 month. Accumulated monthly anomalies of sea surface temperature and air temperature for 6 months showed higher correlation than the anomalies of each month. The magnitudes of sea surface temperature and air temperature anomalies are related with the duration of anomalies. Their magnitudes are large when the durations of anomalies are long.