• 제목/요약/키워드: Delay Diversity

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Student, Dietitian Reactions to Multicultural Food Service in Hannam School District (다문화 음식 급식에 대한 하남지역 중학생의 인식, 만족도, 메뉴 기호도 및 영양사의 태도연구)

  • Kim, Hee-Sup;Lim, Jae-Rong
    • Journal of the Korean Society of Food Culture
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    • 제26권5호
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    • pp.478-489
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    • 2011
  • Student and dietitian reactions to a multicultural food service menu were studied. Food habits in a multicultural family could delay the acculturation of the children to traditional Korean food and could cause the isolation of children from the community. Also, Korean students need to be exposed to other cultures and foods because it can be a challenge to eat novel foods when students grow up. To help both multicultural and Korean children adjust to new foods, a multicultural menu was included in a school's food service. Students regarded the multicultural menu as access to another culture, but they felt that improvement of the food quality and menu diversity were required. The degree of satisfaction with the food quality, appearance, freshness, temperature, and menu diversity were all moderate. The multicultural menu was served as a single menu item or a combination menu item. The main dish single items - pasta, jajangmyeon, onigiri, hamburgers, rice and curry, kaupatmu, kaupatkung, and donburi - were liked, but nasi goreng was liked only moderately. The soup - based dish single item, tempura soba, was liked, while tomyum was disliked. The side dish single items - tangsuyook, Japanese donkatsu, baked sausage and potatoes, tandoori chicken, chicken britto, Vienna schnitzels, tender tortillas, and fried chicken wings - were liked. The desserts single items-sandwiches, pineapples, waffles, pizza, bread with strawberry jam, mangoes, and tacoyaki - were liked. The combination menus - Italian, Indian, and American - were liked, but the southeast Asian menu was the least favored. Acceptance of combination and single menu items were similar. Male students liked multicultural menu items more than female students in all categories. Approximately 60% of dietitians had experience serving the single menu items for multicultural food service. The appropriate serving times were twice per month. Dietitians guessed that 80% of the students liked the multicultural menu. The dietitians preferred serving American or Chinese foods to southeast Asian food. There were two difficulties in serving the multicultural menu, which were voiced as as lack of skill in cooking the items and improper cooking utensils and tableware for the items. Despite all the difficulties, the dietitians served the multicultural menu because it provided menu diversity, rather than for educational reasons.

Efficient Video Streaming System over Heterogeneous Wireless Networks (이종 무선망 환경에서 효과적인 영상 스트리밍 시스템)

  • Joo, Hyun-Chul;Lee, Dong-Ju;Han, Sang-Chun;Song, Hwang-Jun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제37권2B호
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    • pp.110-119
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    • 2012
  • In this paper, we propose an efficient video streaming system over heterogeneous wireless networks. The proposed system modifies fountain code for the video streaming service and maximizes the target video encoding rate using multiple paths while satisfying delay and block recovery failure rate constraints of fountain code. Finally, the proposed system provides the seamless video streaming service of high quality to subscribers by dynamic adaptation of control parameters based on the states of each path over heterogeneous wireless networks.

Mitigation of Inter-Symbol Interference in Underwater Acoustic Communication Using Spatial Filter (공간 필터를 이용한 수중음향통신의 인접 심볼 간 간섭 완화)

  • Eom, Min-Jeong;Park, Ji-Sung;Ji, Yoon-Hee;Kim, J.S.
    • The Journal of the Acoustical Society of Korea
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    • 제33권1호
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    • pp.48-53
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    • 2014
  • The underwater acoustic communication (UAC) is characterized by doubly spread channel. It is included in the time-variant doppler shift and delay-time spreads due to multiple paths. To compensate such distorted signals, various techniques including time-reversal processing, spatial diversity, phase estimator, and equalizer are being applied. In this paper, a spatial filter based on the beamforming is proposed as a method to mitigate such inter-symbol interferences that are generated in time-varying multipath channels. The proposed technique realizes coherent communications by steering the direction of the desired signals and improves the performance of UAC by increasing the signal-to-interference plus noise ratio using the array gain.

A Study on Chanel Estimation Method in OFDM for IEEE 802.11a System (IEEE 802.11a시스템을 위한 OFDM의 채널추정기법에 관한 연구)

  • Kim, Dong-Ok;Oh, Chung-Gyun
    • Journal of The Institute of Information and Telecommunication Facilities Engineering
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    • 제2권4호
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    • pp.17-27
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    • 2003
  • This paper presents the channel estimation method with STBC applied to IEEE802.11a. Tenacious channel estimation method for OFDM system, that generally uses STTC, has been presented once and massive amount of calculation was needed However, regarding this paper, the amount of calculation can be reduced by using Curve Fitting, and channel tracking performance improvement can be achieved Based on the estimation method, computer simulation was done for the performance analysis and delay spread Doppler frequency and many other group sizes and numbers were considered As a result of the testing, we found out that Doppler frequency deviation effects equally as frequency offset. Also compared to the existing technique, channel estimated performance confirmed that have 0.9dB SNR improvement than old method.

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Channel Estimation Method Using Power Control Schemes in Wireless Systems

  • Kim, Byoung-Gi;Ryoo, Sang-Jin
    • Journal of Communications and Networks
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    • 제12권2호
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    • pp.140-149
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    • 2010
  • Green communication is a new paradigm of designing the communication system which considers not only the processing performance but also the energy efficiency. Power control management is one of the approaches in green communication to reduce the power consumption in distributed communication system. In this paper, we propose improved power control schemes for mobile satellite systems with ancillary terrestrial components (ATCs). In order to increase system capacity and reduce the transmitting power of the user's equipment, we propose an efficient channel estimation method consisting of a modified open-loop power control (OLPC) and closed-loop power control (CLPC). The OLPC works well if the forward and reverse links are perfectly correlated. The CLPC is sensitive to round-trip delay and, therefore, it is not effective in a mobile satellite system. In order to solve the above problem, we added monitoring equipment to both the OLPC and CLPC to use information about transmitting power that has not yet been received by the receiver over the satellite/ATC channel. Moreover, we adapted an efficient pilot diversity of both OLPC and CLPC in order to get a better signal to interference plus noise ratio estimation of the received signal.

Improvement of Channel Estimation Algorithm in Mobile/Satellite Communication Systems

  • Kim, Byung-Gi;Ryoo, Sang-Jin;Lee, Chang-Hun;Choi, Kwang-Seok;Kim, Seong-Hwan;Kang, Seong-Jun;Na, Cheol-Hun
    • Journal of information and communication convergence engineering
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    • 제7권3호
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    • pp.404-411
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    • 2009
  • In this paper, in order to increase system capacity and reduce the transmitting power of the user's equipment, we propose an efficient power estimation consisting of a modified open-loop power control (OLPC) and closed-loop power control (CLPC) schemes for mobile/satellite communications systems. The OLPC works well if the forward and reverse links are perfectly correlated and the CLPC is sensitive to round-trip delay (RTD). Therefore, it is not effective in mobile/satellite system. In order to solve the above problem, we added monitoring equipment to both the OLPC and CLPC to use information about transmitting power that has not yet been received by the receiver over the satellite/ATC channel. Moreover, we adapted an efficient pilot diversity of both OLPC and CLPC in order to get a better signal to interference plus noise ratio (SIR) estimation of the received signal.

1q21.1 microdeletion identified by chromosomal microarray in a newborn with upper airway obstruction

  • Kim, Yoon Hwa;Yang, Ju Seok;Lee, Young Joo;Bae, Mi Hye;Park, Kyung Hee;Lee, Dong Hyung;Shin, Kyung-Hwa;Kim, Seung Chul
    • Journal of Genetic Medicine
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    • 제15권1호
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    • pp.34-37
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    • 2018
  • A 1q21.1 microdeletion is an extremely rare chromosomal abnormality that results in phenotypic diversity and incomplete penetrance. Patients with a 1q21.1 microdeletion exhibit neurological-psychiatric problems, microcephaly, epilepsy, facial dysmorphism, cataract, and thrombocytopenia absent radius syndrome. We reported a neonate with confirmed intrauterine growth restriction (IUGR), micrognathia, glossoptosis, upper airway obstruction, facial dysmorphism, and eye abnormality at birth as well as developmental delay at the age of 1 year. These clinical manifestations, except for the IUGR and upper airway obstruction, in the neonate indicated a 1q21.1 microdeletion. Here, we report a rare case of a 1q21.1 microdeletion obtained via paternal inheritance in a newborn with upper airway obstruction caused by glossoptosis and tracheal stenosis.

Fast Cooperative Sensing with Low Overhead in Cognitive Radios

  • Dai, Zeyang;Liu, Jian;Li, Yunji;Long, Keping
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제8권1호
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    • pp.58-73
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    • 2014
  • As is well known, cooperative sensing can significantly improve the sensing accuracy as compared to local sensing in cognitive radio networks (CRNs). However, a large number of cooperative secondary users (SUs) reporting their local detection results to the fusion center (FC) would cause much overhead, such as sensing delay and energy consumption. In this paper, we propose a fast cooperative sensing scheme, called double threshold fusion (DTF), to reduce the sensing overhead while satisfying a given sensing accuracy requirement. In DTF, FC respectively compares the number of successfully received local decisions and that of failed receptions with two different thresholds to make a final decision in each reporting sub-slot during a sensing process, where cooperative SUs sequentially report their local decisions in a selective fashion to reduce the reporting overhead. By jointly considering sequential detection and selective reporting techniques in DTF, the overhead of cooperative sensing can be significantly reduced. Besides, we study the performance optimization problems with different objectives for DTF and develop three optimum fusion rules accordingly. Simulation results reveal that DTF shows evident performance gains over an existing scheme.

Node Incentive Mechanism in Selfish Opportunistic Network

  • WANG, Hao-tian;Chen, Zhi-gang;WU, Jia;WANG, Lei-lei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제13권3호
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    • pp.1481-1501
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    • 2019
  • In opportunistic network, the behavior of a node is autonomous and has social attributes such as selfishness.If a node wants to forward information to another node, it is bound to be limited by the node's own resources such as cache, power, and energy.Therefore, in the process of communication, some nodes do not help to forward information of other nodes because of their selfish behavior. This will lead to the inability to complete cooperation, greatly reduce the success rate of message transmission, increase network delay, and affect the overall network performance. This article proposes a hybrid incentive mechanism (Mim) based on the Reputation mechanism and the Credit mechanism.The selfishness model, energy model (The energy in the article exists in the form of electricity) and transaction model constitute our Mim mechanism. The Mim classifies the selfishness of nodes and constantly pay attention to changes in node energy, and manage the wealth of both sides of the node by introducing the Central Money Management Center. By calculating the selfishness of the node, the currency trading model is used to differentiate pricing of the node's services. Simulation results show that by using the Mim, the information delivery rate in the network and the fairness of node transactions are improved. At the same time, it also greatly increases the average life of the network.

Two Stage Deep Learning Based Stacked Ensemble Model for Web Application Security

  • Sevri, Mehmet;Karacan, Hacer
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제16권2호
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    • pp.632-657
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    • 2022
  • Detecting web attacks is a major challenge, and it is observed that the use of simple models leads to low sensitivity or high false positive problems. In this study, we aim to develop a robust two-stage deep learning based stacked ensemble web application firewall. Normal and abnormal classification is carried out in the first stage of the proposed WAF model. The classification process of the types of abnormal traffics is postponed to the second stage and carried out using an integrated stacked ensemble model. By this way, clients' requests can be served without time delay, and attack types can be detected with high sensitivity. In addition to the high accuracy of the proposed model, by using the statistical similarity and diversity analyses in the study, high generalization for the ensemble model is achieved. Within the study, a comprehensive, up-to-date, and robust multi-class web anomaly dataset named GAZI-HTTP is created in accordance with the real-world situations. The performance of the proposed WAF model is compared to state-of-the-art deep learning models and previous studies using the benchmark dataset. The proposed two-stage model achieved multi-class detection rates of 97.43% and 94.77% for GAZI-HTTP and ECML-PKDD, respectively.