• Journal of the Korean Society of Food Culture
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• v.36 no.6
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• pp.542-554
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• 2021

Institutional foodservice is a type of meal provided to workers in industry and affects the health and psychological wellbeing of workers and productivity. Thus, research on customer satisfaction with institutional foodservice is important. In addition to food industry and food culture developments, the requirements of institutional foodservice customers are diversifying due to COVID-19. Therefore, the purpose of this study was to identify factors that affect customer satisfaction with institutional foodservice using a user-based approach. In this study, the quality of institutional foodservice was defined using customer satisfaction or dissatisfaction, and by using in-depth interview and open coding (a qualitative research method), we derived qualities of institutional foodservice from the user's perspective and compared these with those of previous studies. This study is meaningful as the quality of institutional foodservice was analyzed using a user-based approach, in-depth interview, and open coding and compares results with those of previous studies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.2
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• pp.763-774
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• 2015

Hand posture recognition has been a wide region of applications in Human Computer Interaction and Computer Vision for many years. The problem arises mainly due to the high dexterity of hand and self-occlusions created in the limited view of the camera or illumination variations. To remedy these problems, a hand posture recognition method using 3-D point cloud is proposed to explicitly utilize 3-D information from depth maps in this paper. Firstly, hand region is segmented by a set of depth threshold. Next, hand image normalization will be performed to ensure that the extracted feature descriptors are scale and rotation invariant. By robustly coding and pooling 3-D facets, the proposed descriptor can effectively represent the various hand postures. After that, SVM with Gaussian kernel function is used to address the issue of posture recognition. Experimental results based on posture dataset captured by Kinect sensor (from 1 to 10) demonstrate the effectiveness of the proposed approach and the average recognition rate of our method is over 96%.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.4
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• pp.231-234
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• 2016

The next-generation video coding standard known as High-Efficiency Video Coding (HEVC) was developed with the aim of doubling the bitrate reduction offered by H.264/Advanced Video Coding (AVC) at the expense of an increase in computational complexity. Mode decision with motion estimation is still one of the most time-consuming computations in HEVC, as it is with H.264/AVC. Several schemes for a fast mode decision have been presented in reference software and in other studies. However, a possible speed-up in conventional schemes is sometimes insignificant for videos that have inhomogeneous spatial and temporal characteristics. This paper proposes a bypass algorithm to skip large-block-size predictions for videos where small block sizes are preferred over large ones. The proposed algorithm does not overlap with those in previous works, and thus, is easily used with other fast algorithms. Consequently, an independent speed-up is possible.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.9
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• pp.786-791
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• 2012

This paper presents a depth boundary sharpening method for improved view synthesis in 3D video. In depth coding, distortion occurs around object boundaries, degrading the quality of synthesized images. In order to encounter this problem, the proposed method estimates an edge map for each frame to filter only the boundary regions. In particular, a window-based filter is employed to choose the most reliable pixel as the replacement considering three factors: frequency, similarity and closeness. The proposed method was implemented as post-processing of the deblocking filter in JMVC 8.3.Compared to the conventional methods, the proposed method generated 0.49 dB PSNR increase and 16.58% bitrate decrease on average. The improved portions were subjectively confirmed as well.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.2
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• pp.35-44
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• 2022

In this paper, we propose an intra-picture prediction method by a quadratic surface modeling method for depth video coding. The pixels of depth video are transformed to 3D coordinates using distance information. A quadratic surface with the smallest error is found by least square method for reference pixels. The reference pixel can be either the upper pixels or the left pixels. In the intra prediction using the quadratic surface, two predcition values are computed for one pixel. Two errors are computed as the square sums of differences between each prediction values and the pixel values of the reference pixels. The pixel sof the block are predicted by the reference pixels and prediction method that they have the lowest error. Comparing with the-state-of-art video coding method, simulation results show that the distortion and the bit rate are improved by up to 5.16% and 5.12%, respectively.

• ETRI Journal
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• v.39 no.3
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• pp.301-309
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• 2017

In this paper, we propose a parallelization method for a High Efficiency Video Coding (HEVC) deblocking filter with transform unit (TU) split information. HEVC employs a deblocking filter to boost perceptual quality and coding efficiency. The deblocking filter was designed for data-level parallelism. In this paper, we demonstrate a method of distributing equal workloads to all cores or threads by anticipating the deblocking filter complexity based on the coding unit depth and TU split information. We determined that the average time saving of our proposed deblocking filter parallelization method has a speed-up factor that is 2% better than that of the uniformly distributed parallel deblocking filter, and 6% better than that of coding tree unit row distribution parallelism. In addition, we determined that the speed-up factor of our proposed deblocking filter parallelization method, in terms of percentage run-time, is up to 3.1 compared to the run-time of the HEVC test model 12.0 deblocking filter with a sequential implementation.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.129-135
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• 2019

The purpose of this study is to propose the future development direction of the program which can apply the fusion education in the fourth industrial revolution era to the class and achieve creative problem solving ability. As a research method, we investigated cases of overseas coding education and conducted in - depth interviews with infants and parents. The results of the case study and in-depth interviews were as follows: First, the children were able to do their own preliminary and reviewing at home. Second, to provide an interesting play program for the young children to participate. Third, It is important that parents and children learn together. In future research, it is anticipated that there will be a positive effect by concrete proposal to secure the weaknesses and to combine existing coding education with interesting education in accordance with domestic characteristics.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.196-198
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• 2011

MPEG 과 VCEG 의 공동협력팀인 JCT-VC(Joint Collaboration Team on Video Coding)에서는 H.264/AVC 보다 두 배 이상의 높은 부호화 효율을 목표로 HEVC(High Efficiency Video Coding) 표준화를 진행하고 있다. HEVC 표준화에서는 압축 효율뿐만 아니라 부호화기의 복잡도도 중요하게 고려되고 있다. 본 논문에서는 HEVC 부호화기의 높은 복잡도를 줄이기 위하여 상위 깊이의 부호화 단위(Coding Unit: CU)의 움직임 정보를 이용하여 현재 부호화하는 예측단위(Prediction Unit: PU)의 참조영상의 후보의 수를 제한하는 고속 부호화 알고리즘을 제안한다. 모의실험을 통하여 제안한 알고리즘은 HM3.0 에 비해 평균 10.8% 정도의 부호화 시간을 감소시키며, 이때 평균 비트율은 0.5%로 부호화 효율의 감소가 미미함을 확인 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.3165-3181
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• 2019

Spherical videos, which are also called 360-degree videos, have become increasingly popular due to the rapid development of virtual reality technology. However, the large amount of data in such videos is a huge challenge for existing transmission system. To use the existing encode framework, it should be converted into a 2D image plane by using a specific projection format, e.g. the equi-rectangular projection (ERP) format. The existing high-efficiency video coding standard (HEVC) can effectively compress video content, but its enormous computational complexity makes the time spent on compressing high-frame-rate and high-resolution 360-degree videos disproportionate to the benefits of compression. Focusing on the ERP format characteristics of 360-degree videos, this work develops a fast decision algorithm for predicting the coding unit depth interval and adaptive mode decision for intra prediction mode. The algorithm makes full use of the video characteristics of the ERP format by dealing with pole and equatorial areas separately. It sets different reference blocks and determination conditions according to the degree of stretching, which can reduce the coding time while ensuring the quality. Compared with the original reference software HM-16.16, the proposed algorithm can reduce time consumption by 39.3% in the all-intra configuration, and the BD-rate increases by only 0.84%.

• ETRI Journal
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• v.45 no.4
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• pp.615-626
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• 2023

Under limited transmission conditions, many factors affect the efficiency of video transmission. During the flight of an unmanned aerial vehicle (UAV), frequent network switching often occurs, and the channel transmission condition changes rapidly, resulting in low-video transmission efficiency. This paper presents an efficient video coding flow for UAVs working in the 5G nonstandalone network and proposes two bit controllers, including time and spatial bit controllers, in the flow. When the environment fluctuates significantly, the time bit controller adjusts the depth of the recursive codec to reduce the error propagation caused by excessive network inference. The spatial bit controller combines the spatial bit mask with the channel quality multiplier to adjust the bit allocation in space to allocate resources better and improve the efficiency of information carrying. In the spatial bit controller, a flexible mini graph is proposed to compute the channel quality multiplier. In this study, two bit controllers with end-to-end codec were combined, thereby constructing an efficient video coding flow. Many experiments have been performed in various environments. Concerning the multi-scale structural similarity index and peak signal-to-noise ratio, the performance of the coding flow is close to that of H.265 in the low bits per pixel area. With an increase in bits per pixel, the saturation bottleneck of the coding flow is at the same level as that of H.264.