• Title/Summary/Keyword: adaptive mechanisms

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Cognitive Factors in Adaptive Information Access

  • Park, Minsoo
    • International Journal of Advanced Culture Technology
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    • v.6 no.4
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    • pp.309-316
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    • 2018
  • The main purpose of this study is to understand how cognitive factors influence the way people interact with information/information systems, by conducting comprehensive and in-depth literature reviews and a theoretical synthesis of related research. Adaptive systems have been built around an individual user's characteristics, such as interests, preferences, knowledge and goals. Individual differences in the ability to use new information and communication technology have been an important issue in all fields. Performance differences in utilizing new information and communication technology are sufficiently predictable that we can begin to coordinate them. Therefore, it is necessary to understand cognitive mechanisms to explain differences between individuals as well as the levels of performance. The theoretical synthesis from this study can be applied to design intelligent (i.e., human friendly) systems in our everyday lives. Further research should explore optimization design for user, by integrating user's individual traits (such as emotion and intent) and system modules to improve the interactions of human-system in data-driven environments.

An Adaptive Power Saving Mechanism in IEEE 802.11 Wireless IP Networks

  • Pack Sangheon;Choi Yanghee
    • Journal of Communications and Networks
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    • v.7 no.2
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    • pp.126-134
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    • 2005
  • Reducing energy consumption in mobile hosts (MHs) is one of the most critical issues in wireles/mobile networks. IP paging protocol at network layer and power saving mechanism (PSM) at link layer are two core technologies to reduce the energy consumption of MHs. First, we investigate the energy efficiency of the current IEEE 802.11 power saving mechanism (PSM) when IP paging protocol is deployed over IEEE 802.11 networks. The result reveal that the current IEEE 802.11 PSM with a fixed wakeup interval (i.e., the static PSM) exhibits a degraded performance when it is integrated with IP paging protocol. Therefore, we propose an adaptive power saving mechanism in IEEE 802.11-based wireless IP networks. Unlike the static PSM, the adaptive PSM adjusts the wake-up interval adaptively depending on the session activity at IP layer. Specifically, the MH estimates the idle periods for incoming sessions based on the exponentially weighted moving average (EWMA) scheme and sets its wake-up interval dynamically by considering the estimated idle period and paging delay bound. For performance evaluation, we have conducted comprehensive simulations and compared the total cost and energy consumption, which are incurred in IP paging protocol in conjunction with various power saving mechanisms: The static PSM, the adaptive PSM, and the optimum PSM. Simulation results show that the adaptive PSM provides a closer performance to the optimum PSM than the static PSM.

A Study of Core-Stateless Mechanism for Fair Bandwidth Allocation (대역 공평성 보장을 위한 Core-Stateless 기법 연구)

  • Kim, Hwa-Suk;Kim, Sang-Ha;Kim, Young-Bu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.4C
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    • pp.343-355
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    • 2003
  • Fair bandwidth allocations at routers protect adaptive flows from non-adaptive ones and may simplify end-to end congestion control. However, traditional fair bandwidth allocation mechanisms, like Weighted Fair Queueing and Flow Random Early Drop, maintain state, manage buffera and perform packet scheduling on a per-flow basis. These mechanisms are more complex and less scalable than simple FIFO queueing when they are used in the interi or of a high-speed network. Recently, to overcome the implementation complexity problem and address the scalability and robustness, several fair bandwidth allocation mechanisms without per-flow state in the interior routers are proposed. Core-Stateless Fair Queueing and Rainbow Fair Queuing are approximates fair queueing in the core-stateless networks. In this paper, we proposed simple Layered Fair Queueing (SLFQ), another core-stateless mechanism to approximate fair bandwidth allocation without per-flow state. SLFQ use simple layered scheme for packet labeling and has simpler packet dropping algorithm than other core-stateless fair bandwidth allocation mechanisms. We presente simulations and evaluated the performance of SLFQ in comparison to other schemes. We also discussed other are as to which SLFQ is applicable.

Quality-of-Service Mechanisms for Flow-Based Routers

  • Ko, Nam-Seok;Hong, Sung-Back;Lee, Kyung-Ho;Park, Hong-Shik;Kim, Nam
    • ETRI Journal
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    • v.30 no.2
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    • pp.183-193
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    • 2008
  • In this paper, we propose quality of service mechanisms for flow-based routers which have to handle several million flows at wire speed in high-speed networks. Traffic management mechanisms are proposed for guaranteed traffic and non-guaranteed traffic separately, and then the effective harmonization of the two mechanisms is introduced for real networks in which both traffic types are mixed together. A simple non-work-conserving fair queuing algorithm is proposed for guaranteed traffic, and an adaptive flow-based random early drop algorithm is proposed for non-guaranteed traffic. Based on that basic architecture, we propose a dynamic traffic identification method to dynamically prioritize traffic according to the traffic characteristics of applications. In a high-speed router system, the dynamic traffic identification method could be a good alternative to deep packet inspection, which requires handling of the IP packet header and payload. Through numerical analysis, simulation, and a real system experiment, we demonstrate the performance of the proposed mechanisms.

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Adaptive Gaussian Mechanism Based on Expected Data Utility under Conditional Filtering Noise

  • Liu, Hai;Wu, Zhenqiang;Peng, Changgen;Tian, Feng;Lu, Laifeng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.7
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    • pp.3497-3515
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    • 2018
  • Differential privacy has broadly applied to statistical analysis, and its mainly objective is to ensure the tradeoff between the utility of noise data and the privacy preserving of individual's sensitive information. However, an individual could not achieve expected data utility under differential privacy mechanisms, since the adding noise is random. To this end, we proposed an adaptive Gaussian mechanism based on expected data utility under conditional filtering noise. Firstly, this paper made conditional filtering for Gaussian mechanism noise. Secondly, we defined the expected data utility according to the absolute value of relative error. Finally, we presented an adaptive Gaussian mechanism by combining expected data utility with conditional filtering noise. Through comparative analysis, the adaptive Gaussian mechanism satisfies differential privacy and achieves expected data utility for giving any privacy budget. Furthermore, our scheme is easy extend to engineering implementation.

A Robust and Adaptive Trust Management System for Guaranteeing the Availability in the Internet of Things Environments

  • Wu, Xu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.5
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    • pp.2396-2413
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    • 2018
  • Trust management is one of the most challenging issues for the highly heterogeneous Internet of Things (IoT). In the context of the IoT, it is difficult to evaluate the node's trustworthiness in the same trust model when a node provides different services. Guaranteeing the availability of the trust management service is another significant challenge because of the dynamic nature of IoT environments. With these issues in mind, this paper propose a robust and adaptive trust management system for the IoT that is able to measure the trustworthiness of nodes based on feedbacks collected from participants in a specific context and ensure the availability of trust management services. The main contributions of our system are: 1) Proposing a partly decentralized trust management framework, which improves the resiliency of the trust mechanism; 2) Proposing an adaptive trust evaluation scheme and a three-dimensional context representation makes trust evaluation more accurate and specific; 3) Enhancing the adaptive trust evaluation scheme by incorporating a bad behavior factor in trust estimation, which efficiently distinguishes misleading feedbacks from On-Off attacks. Simulation results show the good performance of the proposed system and especially show effectiveness against On-Off attacks compared to other trust mechanisms.

Traffic Adaptive Wakeup Control Mechanism in Wireless Sensor Networks (무선 센서 네트워크에서 트래픽 적응적인 wakeup 제어 메커니즘)

  • Kim, Hye-Yun;Kim, Seong-Cheol;Jeon, Jun-Heon;Kim, Joon-Jae
    • Journal of Korea Multimedia Society
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    • v.17 no.6
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    • pp.681-686
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    • 2014
  • In this paper, we propose a traffic adaptive mechanism that controls the receiver's wakeup periods based on the generated traffic amounts. The proposed control mechanism is designed for military, wild animal monitoring, and forest fire surveillance applications. In these environments, a low-rate data transmission is usually required between sensor nodes. However, continuous data is generated when events occur. Therefore, legacy mechanisms are ineffective for these applications. Our control mechanism showed a better performance in energy efficiency compared to the RI-MAC owing to the elimination of the sender node's idle listening.

Understanding the Roles of Host Defense Peptides in Immune Modulation: From Antimicrobial Action to Potential as Adjuvants

  • Ju Kim;Byeol-Hee Cho;Yong-Suk Jang
    • Journal of Microbiology and Biotechnology
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    • v.33 no.3
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    • pp.288-298
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    • 2023
  • Host defense peptides are expressed in various immune cells, including phagocytic cells and epithelial cells. These peptides selectively alter innate immune pathways in response to infections by pathogens, such as bacteria, fungi, and viruses, and modify the subsequent adaptive immune environment. Consequently, they play a wide range of roles in both innate and adaptive immune responses. These peptides are of increasing importance due to their broad-spectrum antimicrobial activity and their functions as mediators linking innate and adaptive immune responses. This review focuses on the pleiotropic biological functions and related mechanisms of action of human host defense peptides and discusses their potential clinical applications.

Infection and Innate Immunityi (감염과 선천면역)

  • Oh, Moo-Young
    • Clinical and Experimental Pediatrics
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    • v.48 no.11
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    • pp.1153-1161
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    • 2005
  • As known by other name(natural immunity), the innate immune system comprises all those mechanisms for dealing with infection that are constitutive or built in, changing little with age or with experience of infection. Though in some ways less sophisticated than adaptive immunity, innate immunity should not belittled, since it has evidently protected thousands of species of invertebrates sufficiently to survive for up to 2 billion years. In the innate immune system, molecules of both cellular and humoral types are involved, corresponding to the need to recognize and dispose of different types of pathogen, to promote inflammatory responses and to interact to the adaptive immune system. A major features of innate immunity are the presence of the normal gut flora, complements, macrophages, dendritic cells, natural killer cells and many cytokines that can block the establishment of infection. Both phagocytic cells and complement system have tremendous potential for damaging host cells, but fortunately they are normally only triggered by foreign materials, and usually most of their destructive effects are focussed on the surface of these or in the safe environment of the phagolysosome. This article addreses the comprehensive mechanisms of the major components of the innate immune system to prevent the infection.

Improve ARED Algorithm in TCP/IP Network (TCP/IP 네트워크에서 ARED 알고리즘의 성능 개선)

  • Nam, Jae-Hyun
    • Journal of the Korea Society of Computer and Information
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    • v.12 no.3
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    • pp.177-183
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    • 2007
  • Active queue management (AQM) refers to a family of packet dropping mechanisms for router queues that has been proposed to support end-to-end congestion control mechanisms in the Internet. The proposed AQM algorithm by the IETF is Random Early Detection (RED). The RED algorithm allows network operators simultaneously to achieve high throughput and low average delay. However. the resulting average queue length is quite sensitive to the level of congestion. In this paper, we propose the Refined Adaptive RED(RARED), as a solution for reducing the sensitivity to parameters that affect RED performance. Based on simulations, we observe that the RARED scheme improves overall performance of the network. In particular, the RARED scheme reduces packet drop rate and improves goodput.

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