• Title/Summary/Keyword: Media Access Control

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A Study on the Characteristics of Information Design in Multimedia Design (멀티미디어디자인에서 정보디자인 특성에 관한 연구)

  • 류시천
    • Archives of design research
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    • v.17 no.1
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    • pp.63-76
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    • 2004
  • Although information design principles had originated from the graphic design field including publishing design in 1970s, information design have taken one of the most important positions in multimedia design fields as the present since Richard Saul Wurmn started his researches on information design and its practical application on internet environments. However, relatively little researches have been performed for building identity of information design in multimedia design fields so far and moreover in some cases, information design is likely to be narrowly viewed as 'the representation of a piece of information and its visualization' which was defined in traditional graphic design field. This research circumstance leads the study to investigate characteristics of information design in current multimedia design with contingent perspective which is compared to the traditional information design. The study results suggest 5 characteristics of information design including 'suggesting context & finding out information hierarchy', 'access of integrated consideration & share of information control', 'using of multi-dimensional media & content first', 'stabilization of information quality & combinational understanding of meaning', 'bilateral information representation & user's knowledge expansion'. Future researches, based on the results of the study, are expected to be expanded to a degree with argument for inter-dependent and/or exclusive characteristics of adjacent fields of information design such as interface design, interaction design and experience design.

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LP-MAC Technique in association with Low Power operation in unmanned remote wireless network (무인원격 무선 네트워크 환경에서의 저전력 운용을 고려한 LP-MAC 기법)

  • Youn, Jong-Taek;Ryu, Jeong-Kyu;Kim, Yongi
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.8
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    • pp.1877-1884
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    • 2014
  • Because of the limited power resource, we need a reliable low-power media access control technique suitable for unmaned remote sensor operation condition for the unmanned sensor processor to perform the task in the remote wireless network situation. Therefore CSMA/CA and X-MAC is generally considered to effectively transmit the signal in the low-power wireless network. In this paper, we propose the more efficient low-power LP-MAC Technique which consumes the minimum power and transmits the data faster in condition that the mobile nodes' joining to and leaving from the network which consists of the fixed nodes is fluid. The fixed nodes operate in an asynchronous mode to perform the network self-configuration and transmit data faster to the mobile node which is frequently join and leave the network. When the mobile node leaves the network, the network's operation mode will be synchronous mode to achieve the minimum power consumption, thus the minimum power operation becomes possible.

Ultrasonic wireless sensor development for online fatigue crack detection and failure warning

  • Yang, Suyoung;Jung, Jinhwan;Liu, Peipei;Lim, Hyung Jin;Yi, Yung;Sohn, Hoon;Bae, In-hwan
    • Structural Engineering and Mechanics
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    • v.69 no.4
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    • pp.407-416
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    • 2019
  • This paper develops a wireless sensor for online fatigue crack detection and failure warning based on crack-induced nonlinear ultrasonic modulation. The wireless sensor consists of packaged piezoelectric (PZT) module, an excitation/sensing module, a data acquisition/processing module, a wireless communication module, and a power supply module. The packaged PZT and the excitation/sensing module generate ultrasonic waves on a structure and capture the response. Based on nonlinear ultrasonic modulation created by a crack, the data acquisition/processing module periodically performs fatigue crack diagnosis and provides failure warning if a component failure is imminent. The outcomes are transmitted to a base through the wireless communication module where two-levels duty cycling media access control (MAC) is implemented. The uniqueness of the paper lies in that 1) the proposed wireless sensor is developed specifically for online fatigue crack detection and failure warning, 2) failure warning as well as crack diagnosis are provided based on crack-induced nonlinear ultrasonic modulation, 3) event-driven operation of the sensor, considering rare extreme events such as earthquakes, is made possible with a power minimization strategy, and 4) the applicability of the wireless sensor to steel welded members is examined through field and laboratory tests. A fatigue crack on a steel welded specimen was successfully detected when the overall width of the crack was around $30{\mu}m$, and a failure warnings were provided when about 97.6% of the remaining useful fatigue lives were reached. Four wireless sensors were deployed on Yeongjong Grand Bridge in Souht Korea. The wireless sensor consumed 282.95 J for 3 weeks, and the processed results on the sensor were transmitted up to 20 m with over 90% success rate.

ECU Data Integrity Verification System Using Blockchain (블록체인을 활용한 ECU 데이터 무결성 검증 시스템)

  • Sang-Pil, Byeon;Ho-Yoon, Kim;Seung-Soo, Shin
    • Journal of Industrial Convergence
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    • v.20 no.11
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    • pp.57-63
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    • 2022
  • If ECU data, which is responsible for collecting and processing data such as sensors and signals of automobiles, is manipulated by an attack, it can cause damage to the driver. In this paper, we propose a system that verifies the integrity of automotive ECU data using blockchain. Since the car and the server encrypt data using the session key to transmit and receive data, reliability is ensured in the communication process. The server verifies the integrity of the transmitted data using a hash function, and if there is no problem in the data, it is stored in the blockchain and off-chain distributed storage. The ECU data hash value is stored in the blockchain and cannot be tampered with, and the original ECU data is stored in a distributed storage. Using the verification system, users can verify attacks and tampering with ECU data, and malicious users can access ECU data and perform integrity verification when data is tampered with. It can be used according to the user's needs in situations such as insurance, car repair, trading and sales. For future research, it is necessary to establish an efficient system for real-time data integrity verification.

A Study on the Agenda Setting Process of Teacher's Certification System in China (중국 교사자격제도의 의제설정 과정 분석)

  • Li, Yu-Yan;Jang, Seon-Hee;Chung, Jae-Young
    • Korean Journal of Comparative Education
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    • v.28 no.4
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    • pp.249-272
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    • 2018
  • The purpose of this study is to analyze which group led the process of agenda setting of teacher's certification system in China from 1978 to 2018 using the Cobb & Elder's theoretical model. The period of about 40 years from 1978 to 2018 is divided into the introduction period of teacher's certification period (1978~1992), transition period (1993~1998), and stabilization stage (1999~2018). The agenda setting process was analyzed. As a result, the group that led the process of agenda setting of the Chinese teacher's certification system varied according to the period. The introduction period of teacher's certification system was analyzed as 'Inside Access Model' led by policy makers and government, and the transition period was confirmed as 'Mobilization Model' led by Chinese government and Ministry of Education. The stabilization period was analyzed as 'Outside Initiative Model' led by various groups such as mass media, researchers, and government. It was found that the process of agenda setting of teacher's certification system had been changing toward democratization according to the degree of development of Chinese society, and the quality control of teacher certifications had been strengthened.

New Retransmission Method using the minimum MPDU starting Spacing in Two-level Aggregation of IEEE 802.11n (IEEE 802.11n의 2-레벨 집적 방식에서 최소 MPDU 시작 간격을 이용하는 새로운 재전송 방법)

  • Shin, In Cheol;Kim, Dong-Hoi
    • Journal of Broadcast Engineering
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    • v.20 no.2
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    • pp.300-309
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    • 2015
  • In IEEE 802.11n WLANs(Wireless Local Area Networks), to support high throughput, MAC(Media Access Control) layer adopts A-MSDU(Aggregate-MAC Service Data Unit) and A-MPDU(Aggregate-MAC Protocol Data Unit). Generally, as the A-MPDU uses a selective retransmission capability, A-MPDU provides higher throughput than A-MSDU. However, although A-MPDU uses the selective re-transmission capability, if the size of MPDU within A-MPDU is smaller than the size of minimum MPDU starting spacing, A-MPDU can reduce throughput because of the overhead of retransmission owing to the addition of delimiter, that is a dummy MPDU. Therefore, to overcome the above problem, two-level Aggregation method, where the small MPDU within A-MPDU is replaced by not delimiter but A-MSDU, has been introduced. In the two-level Aggregation method, the existing re-transmission scheme retransmits only A-MPDU, but if the size of retransmission data is smaller than the size of the minimum MPDU starting spacing, the proposed retransmission scheme retransmits the aggregated retransmission data and MSDUs. Therefore, we know that the proposed retransmission scheme have better throughput that the existing retransmission scheme.

Knowledge and Attitude Towards Tobacco Smoking among 13-15 Year-Old School Children in Viet Nam - Findings from GYTS 2014

  • Nguyen, Thanh Huong;Nguyen, Trung Kien;Kim, Bao Giang;Hoang, Van Minh;Phan, Thi Hai;Doan, Thu Huyen;Luong, Ngoc Khue;Nguyen, Thuy Linh;Nguyen, Tuan Lam;Pham, Thi Quynh Nga
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.sup1
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    • pp.37-42
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    • 2016
  • Studies have shown that smoking is a learnt behavior, often initiated during adolescence. This paper aims to describe tobacco-related knowledge, attitude and associations among school adolescents aged 13-15 with exposure to anti-smoking information. Using data from the Global Youth Tobacco Survey (GYTS) in Viet Nam, 2014, knowledge was measured through 4 questions about tobacco use, and attitude was assessed through 3 questions on personal, social and environmental aspects. Students giving most anti-tobacco responses to all questions were considered as having correct knowledge or appropriate attitude or both. Access to anti-smoking information was determined by exposure to any media messages on tobacco control during the past 30 days and teaching in school about the danger of tobacco use during the past 12 months. A substantial percentage of students thought that being near others who smoke might be harmful to them and smoking is harmful to health (89.4% and 89.6% respectively). However, only 46.4% reported that it is definitely difficult to quit smoking and 66.9% thought that smoking for only 1 or 2 years, once stopped, is harmful to health. Slightly more than half of the respondents reported appropriate attitude that young smokers have fewer friends than others and smoking makes them less attractive and less comfortable at social events. Noticing anti-smoking messages in the media together with having lessons in school about the dangers of tobacco substantially increased the likelihood of having correct knowledge, appropriate attitude and both. Despite relatively high awareness about smoking harms, effective educational communication is still highly needed to improve the level of comprehensive knowledge and an appropriate attitude regarding tobacco use.

Conceptual Design of Networking Node with Real-time Monitoring for QoS Coordination of Tactical-Mesh Traffic (전술메쉬 트래픽 QoS 조율을 위한 네트워킹 노드의 개념 설계 및 실시간 모니터링)

  • Shin, Jun-Sik;Kang, Moonjoong;Park, Juman;Kwon, Daehoon;Kim, JongWon
    • Smart Media Journal
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    • v.8 no.2
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    • pp.29-38
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    • 2019
  • With the advancement of information and communication technology, tactical networks are continuously being converted to All-IP future tactical networks that integrate all application services based on Internet protocol. Futuristic tactical mesh network is built with tactical WAN (wide area network) nodes that are inter-connected by a mesh structure. In order to guarantee QoS (quality of service) of application services, tactical service mesh (TSM) is suggested as an intermediate layer between infrastructure and application layers for futuristic tactical mesh network. The tactical service mesh requires dynamic QoS monitoring and control for intelligent QoS coordination. However, legacy networking nodes used for existing tactical networks are difficult to support these functionality due to inflexible monitoring support. In order to resolve such matter, we propose a tactical mesh WAN node as a hardware/software co-designed networking node in this paper. The tactical mesh WAN node is conceptually designed to have multi-access networking interfaces and virtualized networking switches by leveraging the DANOS whitebox server/switch. In addition, we explain how to apply eBPF-based traffic monitoring to the tactical mesh WAN node and verify the traffic monitoring feasibility for supporting QoS coordination of tactical-mesh traffic.

CAMAR: Context-Aware Mobile AR System for Personalized Smart Object Control and Media Contents Provision in Ubiquitous Computing Environment (유비쿼터스 환경에서 개인화된 스마트 오브젝트 제어 및 미디어 콘텐츠 제공을 위한 맥락 인식 모바일 증강 현실 시스템)

  • Suh, Young-Jung;Park, Young-Min;Yoon, Hyo-Seok;Woo, Woon-Tack
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.44 no.3
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    • pp.57-67
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    • 2007
  • Researchers in mobile AR systems have so far put the value on the technical challenges involved in the limitations imposed from mobility. Beyond such immediate technical questions, however, are questions regarding the possible contents that are to be used for the user’s interaction in ubiquitous computing environment. Various aspects of context of user and environment can be utilized easily as well as effectively. Moreover, the environment will be equipped with lots of pervasive but invisible computing resources. However, it is difficult for users to have access to those computing resources. At the same time, as the smart appliances get to have more features, their user interfaces tend to become harder to use. Thus, in this paper, we propose Context-Aware Mobile Augmented Reality (CAMAR) system. In our system, users only need to take a picture of smart appliances with a built-in camera in a mobile device when they intend to control the appliances. It lets users interact with the smart appliances through personalized control interfaces on their mobile devices. Also, it supports enabling contents to be not only personalized but also shared selectively and interactively among user communities.

Performance Analysis of the Gated Service Scheduling for Ethernet PON (Ethernet PON을 위한 Gated Service 스케줄링의 성능분석)

  • 신지혜;이재용;김병철
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.41 no.7
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    • pp.31-40
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    • 2004
  • In this paper, we analyze mathematically the performance of the gated service scheduling in the Interleaved Polling with Adaptive Cycle Time(IPACT) was proposed to control upstream traffic for Gigabit Ethernet-PONs. In the analysis, we model EPON MAC protocol as a polling system and use mean value analysis. We divide arrival rate λ into three regions and analyze each region accordingly In the first region in which λ value is very small, there are very few ONUs' data to be transmitted. In the second region in which λ has reasonably large value, ONUs have enough data for continuous transmission. In the third region, ONUs' buffers are always saturated with data since λ value is very large. We obtain average packet delay, average Queue size, average cycle time of the gated service. We compare analysis results with simulation to verify the accuracy of the mathematical analysis. Simulation requires much time and effort to evaluate the performance of EPONs. On the other hand, mathematical analysis can be widely used in the design of EPON systems because system designers can obtain various performance results rapidly. We can design appropriate EPON systems for varioustraffic property by adjusting control parameters.