Korea Educational Broadcasting System

Fine-grained video classification requires understanding complex spatio-temporal and semantic cues that often exceed the capacity of a single modality. In this paper, we propose a multimodal framework that fuses video, image, and text representations using GRU-based sequence encoders and cross-modal attention mechanisms. The model is trained using a combination of classification or regression loss, depending on the task, and is further regularized through feature-level augmentation and autoencoding techniques. To evaluate the generality of our framework, we conduct experiments on two challenging benchmarks: the DVD dataset for real-world Violence Detection and the Aff-Wild2 dataset for Valence-Arousal estimation. Our results demonstrate that the proposed fusion strategy significantly outperforms unimodal baselines, with cross-attention and feature augmentation contributing notably to robustness and performance. The code used in the 9th ABAW competition is available at https://github.com/namho-96/ABAW-9th.

GPP standard was recently revised to support bandwidths of 6/7/8 MHz to support terrestrial broadcasting bandwidths in 5G Broadcast. ATSC 3.0 and 5G Broadcast are currently regarded as the most highly-developed systems supporting terrestrial broadcasting services for mobile handheld receivers. As mobile broadcasting services are expected to expand globally, we implemented FPGA-based hardware and conducted laboratory and field tests based on it to compare and analyze the physical layer performance of the two standards. The measurement results show that ATSC 3.0 outperforms 5G Broadcast in most cases thanks to a well-designed bit interleaved coded modulation and time interleaver that can adequately handle burst errors occurring in wireless channel.

This paper proposes several realistic fading channel models to describe the signal distortions that arise in single frequency network (SFN) environments. The proposed models characterize ultra-high frequency (UHF) wireless channels based on measurements from operating networks in metropolitan areas. In this paper, the unique features of SFN transmission are identified compared to the conventional, single antenna transmission channels. The impacts of urban propagation, tower configuration, and mobile and terrain effects are considered based on the tapped delay line structure. The proposed models can provide a useful reference to facilitate the SFN system design, network planning, verification, and receiver performance test. Free MATLAB source code of the fading simulator is available at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/ETRI-KMOU/FadingChannelSimulator</uri> .

To overcome considerable path loss in millimeterwave propagation, high-gain directional beamforming is considered to be a key enabling technology for outdoor 5G mobile networks. Associated with beamforming, this paper investigates propagation power loss characteristics in two aspects. The first is beamwidth effects. Owing to the multipath receiving nature of mobile environments, it is expected that a narrower beamwidth antenna will capture fewer multipath signals, while increasing directivity gain. If we normalize the directivity gain, this narrowbeamwidth reception incurs an additional power loss compared to omnidirectional-antenna power reception. With measurement data collected in an urban area at 28 GHz and 38 GHz, we illustrate the amount of these additional propagation losses as a function of the halfpower beamwidth. Secondly, we investigate power losses due to steering beam misalignment, as well as the measurement data. The results show that a small angle misalignment can cause a large power loss. Considering that most standard documents provide omnidirectional antenna path loss characteristics, these results are expected to contribute to mmWave mobile system designs.

For efficient spectral utilization of satellite channels, a shared band transmission technique is introduced in this paper. A satellite transmits multiple received signals from a gateway and terminal in the common frequency band by superimposing the signals. To improve the power efficiency as well as the spectral efficiency, a travelling wave tube amplifier in the satellite should operate near the saturation level. This causes a nonlinear distortion of the superimposed transmit signal. Without mitigating this nonlinear effect, the self‐interference cannot be properly cancelled and the desired signal cannot be demodulated. Therefore, an adaptive compensation scheme for nonlinearity is herein proposed with the proper operation scenario. It is shown through simulations that the proposed shared band transmission approach with nonlinear compensation and self‐interference cancellation can achieve an acceptable system performance in nonlinear satellite channels.

본 연구는 문제풀이 중심으로 운영되는 고등학교 생명과학 수업에서 교육매체의 일종인 교실응답시스템(CRS)의 활용 가능성을 알아보고자 하였다. 교수 학습 전략으로 CRS 활용반(34명)은 학생들이 CRS단말기로 응답한 결과를 교사가 즉시 파악하고 개인별 응답 이유를 질문한 후 피드백을 하였다. 비교반(35명)에서는 CRS를 사용하지 않았으며 학생들에게 일괄적인 피드백을 하였다. 연구 결과, CRS 활용이 학생들로 하여금 수업 활동에 흥미와 집중력을 높여주는 것으로 인식되었다. 그러나 학업 성취도의 향상에 있어서 CRS 활용반과 비교반 사이에 유의한 차이는 없었다. 다만 성적 수준에 따라 그룹을 나누었을 때, 중위그룹에서는 CRS 활용반과 비교반 사이에 학업 성취도의 향상에 유의한 차이를 보였다. 진단평가 및 형성평가에서 CRS 활용의 효과를 높이기 위해서는 다양한 수준의 문제들을 사전에 개발하고, 학생들의 응답 이유를 정확히 파악하여 더욱 많은 학생들에게 개인별 맞춤형 피드백을 할 수 있는 교수 전략의 개발이 필요함을 제안한다. The purpose of this study was to examine the potential of the use of the Classroom Response System (CRS), a kind of new ICT medium, in a quiz problem-solving oriented high school life science class. To find the usefulness of CRS as a teaching and learning strategy, the CRS group (n=34) sent prompt individual answers to the teachers' questions using the CRS terminal (Clicker), and the teacher then asked additional reasons of the individuals and gave personalized feedback. In the control group (n=35), the CRS was not used while the teacher asked overall questions and gave feedback in an undifferentiated way. As a result, the CRS increased students' interest and concentration during class, but there were no significant differences in study achievement between the two groups. However, there were significant differences between the medium-level groups when the two groups were divided into smaller ones based on their pre-scores. We suggest that, for effective use of the CRS for diagnostic and formative assessment, teachers should develop a teaching and learning strategy that can produce appropriate questions of various levels in advance, investigate the exact reasons for students' answers, and give customized feedback by individual as much as possible.

This paper presents a system architecture and information retrieval strategy for multimedia content which exploits descriptive metadata as well as domain ontology. We propose a query processing model including a semantic ranking scheme which can retrieve multimedia objects semantically relevant to the user query and provide users with a search result categorized by concepts and ordered by their semantic relevance to the query. By experiments on a prototype system using a repository of broadcast TV programs, we show effectiveness of the ontology-based multimedia search approach proposed in the paper.

News photographs of international events serve Americans as a visual medium for understanding other cultures and countries. However, a content analysis of 60 years of Pulitzer Prize-winning photographs (1942-2002) reveals that the major visual themes of the prize-winning photographs depicting international news events are predominantly about war and coups. On the other hand, the Pulitzer Prize-winning photographs taken in the US reveal more diverse themes and subjects, although they, too, tend to concentrate on bad news, like crime and terrorism, social problems, racism and poverty. Based on the content analysis and personal interviews with the judges, it is believed that the Prize’s most important determinants of international news photography appear to be violence and conflict with a consideration of the photographers’ demonstration of courage producing the pictures.

We have improved the HD stereoscopic camera system reported last year. Though the previous version shows good performance in many aspects, we felt some more accurate control mechanism should be realized after various types of trial shooting in field. So we have changed several parts of it. For controlling the separation between two cameras and the convergence of the parallel-axis style stereoscopic camera system, we replaced the linear motor system in the first version with small DC motors. And by changing the lens with full-digitally controlled HD lens, we could control both of the lenses more accurately. For the preparation of the real-time image composition with computer graphics, namely mixed-reality, in this version we fixed the updating frequency of the camera parameters to 60 Hz. In addition, for better zoom-convergence interlocked control, we made the look-up table with much more steps so even smoother operation of zoom-convergence control is accomplished. And, we have done subjective evaluation test on the acquired pictures. As we have implemented the function of storing and retrieving the major parameters of the stereoscopic camera, we could precisely analyze the relationship between the result of picture quality assessment and the camera parameters.