• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.837-842
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• 2008

Any errors that are generated in the channels and networks distort the video quality and are propagated in both the spatial and temporal domains. In particular, header errors ran result in serious visual degradation of the output video encoding/decoding schemes that can make an error resilient compressed bit-stream in error prone environments, such as mobile networks. In this paper, we proposes an header error resilience method that consider the activity of macroblock in video bitstream syntex. The extract of header error repaetedly embeds the header parameters into the least significant bits(LSB) of the quantized DCT coefficients prior to VLC. Experimental results show that the proposed error resilience method restores good image quality despite the detected error on header parameters.

• Journal of IKEEE
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• v.11 no.4
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• pp.171-177
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• 2007

Although the Distributed Coordination Function is the fundamental access protocol of IEEE 802.11, it cannot meet the Quality of Service (QoS) requirements in general. So, the Point Coordinate Function is provided to support QoS related services. However, it has inherent problems. Access point (AP) has no knowledge of the queue status and instantaneous channel condition of stations in the system. In this paper we propose an efficient and versatile polling scheduler that shows excellent throughput and fairness performance. Comparison with well known polling schemes is provided through computer simulation under various channel situations including error prone environments.

• Journal of Broadcast Engineering
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• v.7 no.4
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• pp.335-344
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• 2002

A sub-picture slice structure is proposed which can perform the region-of-interest coding effectively, where the subjective quality can be improved by coding the region-of-interest in higher quality than the background region. In addition, the bit allocation mechanism is Proposed where the interval between quantization parameters of the foreground and background region is fixed. And the method to reduce the boundary effect between the foreground and background region is proposed. The foreground region is better protected to the network channel error than the background region. which results in the overall subjective quality improvement in the error prone environments.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.6
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• pp.565-574
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• 2002

We propose an algorithm for the robust transmission of video in error prone environment based on multiple description (MD) scheme and simple rate-distortion operators. The redundancy rate-distortion (RRD) criteria is used to split a one-layer compressed video stream into two correlated descriptions. The proposed algorithm can find more candidate points on the RRD curve than the conventional RRD based methods. A new distortion measure is also defined in this paper, which considers more realistic error environments. Since the proposed MD video coder is based on the standard H.263 coder, each description can be decoded independently by the standard H.263 decoder. Also, several descriptions can be decoded into a single stream by additional merge stage and the H.263 decoder. Simulation results show that the proposed MD video coder yields better performance than the conventional MD splitting algorithm at all bitrates both in single and two description cases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.5
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• pp.447-455
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• 2014

In this paper, we consider a representative integral imaging method in glasses-free 3D image processing and propose a prioritized transmission scheme for guaranteeing a received video quality in error-prone environments. According to the correlation of pixels consisting of each voxel of integral image, we set the priority differently and apply the modulation level according to this priority value. That is to say, the corresponding pixels with small variance are set to a high priority and transmitted by using a low level modulation that is robust under transmission errors, but the corresponding pixels with greater variance are set to a lower priority and transmitted by using a high level modulation that has a high bit error rate but fast transmission rate. Result shows that the proposed scheme that applies the error-robust modulation level to the important image bit stream with the high priority improves the peak to sidelobe ratio (PSR) of the received 3D image, compared with a typical method that use the same modulation level without distinction of priorities.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1183-1186
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• 2004

In the steel production line, the molten metal of a furnace is transformed into billet and then moves to the heating furnace of the hot rolling mill. This paper describes about the realtime billet characters recognition system in the steel production line. Normally, the billets are mixed at yard so that their identifications are very difficult and very important processing. The character recognition algorithm used in this paper is base on the subspace method by K-L transformation. With this method, we need no special feature extraction steps, which are usually error prone. So the gray character images are directly used as input vectors of the classifier. To train the classifier, we have extracted eigen vectors of each character used in the billet numbers, which consists of 10 arabia numbers and 26 alphabet aharacters, which are gathered from billet images of the production line. We have developed billet characters recognition system using this algorithm and tested this system in the steel production line during the 8-days. The recognition rate of our system in the field test has turned out to be 94.1% (98.6% if the corrupted characters are excluded). In the results, we confirmed that our recognition system has a good performance in the poor environments and ill-conditioned marking system like as steel production plant.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.188-197
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• 2020

Due to hazardous working environments at complex, unstructured, and dynamic construction sites, workers frequently face potential safety and health risks throughout the construction process. In this regard, addressing safety challenges remains one of the top priorities. Construction workers' ability to identify and assess risks is acquired through training, which is one of the primary key factors to determine their safety and wellbeing in hazardous working environments. As such, safety managers constantly focus on the effectiveness of the training materials provided to the workers. However, the construction workers are considerably at greater risk of injuries and fatalities compared to the workers in other industries. In this regard, further studies are required to build up a body of knowledge on the conventional safety training approaches as well as their evaluation techniques in order to boost up the adoption by the practitioners in a widespread manner. This paper provides a systematic review of the current safety training approaches and the various techniques for measuring their effectiveness. The attributes of the current safety training methods for construction workers and their evaluation techniques are identified and analyzed. Results indicated that: 1) immersive environment-based training methods are effective than the traditional safety training methods; 2) this effectiveness can be empirically supported by evaluation strategies, but the current techniques are subjective, intrusive, and error-prone. This research offers fresh opportunities to investigate the training strategies by objectively monitoring the physiological responses of construction crews. The results of this study can be used by researchers and practitioners to identify and determine optimal safety training programs that could potentially become ubiquitous in the construction industry.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.4
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• pp.16-21
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• 2000

Role Based Access Control(RBAC) reduces the cost of administering access control policies as well as making the process less error-prone. Administration tool is most important component in the concept of RBAC. The administration tool for the RBAC security system must be maintain the integrity of user-role and role-role relationships in the RBAC Database. Therefor, it is required set functions, properties defining integrity of database. When it will be designed security systems which is applying RBAC policy on the Linux(server system environments, this paper defines integrity of database for user-role and role-role relationships, and we propose formal specification of operation in order to manage these relationships. The proposed formal specification leads to the consistency requirements for the RBAC database which are defined as a set of relationship. Also, this paper can easily derive the implementation of the RBAC administration tool by formal specification of operations. It leads us tn the minimal set for a more efficiently implementation of administration tool.

• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.457-462
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• 2014

Indoor-positioning systems are useful to various applications. Navigation system is one of the most popular applications, which needs the information of directions of nodes' movements. Specifically the applications should get the information in real-time to properly show the current moving position of a node. In this paper, simple vector-based algorithms are proposed to compute amount and direction of changes of azimuth of mobile nodes' heading directions using existing indoor positioning systems in indoor environments where azimuth sensors do not work properly. Previous algorithms calculate the azimuth changes by too many steps of topology-based formula. The algorithms proposed in this paper get the amount of changes of azimuth by simple formula based on vector, and determine the direction of changes by the sign of value of simple formula based on the previous movement of nodes. The algorithms are much simpler and less error-prone than previous ones, and then they can detect changes in many location-based applications as well. The performance of the algorithms is proved logically and mathematically.

• KNOM Review
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• v.23 no.2
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• pp.29-41
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• 2020

Networks are growing faster than ever before causing a multi-domain complexity. The diversity, variety and dynamic nature of network traffic and services require enhanced orchestration and management approaches. While many standard orchestrators and network operators are resulting in an increase of complexity for handling E2E slice orchestration. Besides, there are multiple domains involved in E2E slice orchestration including access, edge, transport and core network each having their specific challenges. Hence, handling of multi-domain, multi-platform and multi-operator based networking environments manually requires specified experts and using this approach it is impossible to handle the dynamic changes in the network at runtime. Also, the manual approaches towards handling such complexity is always error-prone and tedious. Hence, this work proposes an automated and abstracted solution for handling E2E slice orchestration using an intent-based approach. It abstracts the domains from the operators and enable them to provide their orchestration intention in the form of high-level intents. Besides, it actively monitors the orchestrated resources and based on current monitoring stats using the machine learning it predicts future utilization of resources for updating the system states. Resulting in a closed-loop automated E2E network orchestration and management system.