• 제목/요약/키워드: Critical Node

검색결과 284건 처리시간 0.021초

Dynamic calculation of a tapered shaft rotor made of composite material

  • Rachid, Zahi;Kaddour, Refassi;Achache, Habib
    • Advances in aircraft and spacecraft science
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    • 제5권1호
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    • pp.51-71
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    • 2018
  • This work proposes a theoretical and numerical study on the behavior of a tapered shaft rotor made of composite materials by the classical version h and the version p of the finite element method. Hierarchical form functions are used to define the model. The purpose of this paper is to determine the expressions of the kinetic and potential energies of the tree necessary for the results of the equations of motion. A comparison between the version h and the p version of the finite element method of the functions of polynomial and trigonometric hierarchical forms with six degrees of freedom per node, of a composite tapered and cylindrical shaft which rotates at a constant speed about its axis. It is found that when the number of functions of form (the version p) is increased, the solution converges. It is also observed that the conicity of the shaft increases the rigidity with respect to a uniform shaft having the same mechanical properties. The numerical simulation allowed us to determine the natural frequencies and the critical speeds of the composite shaft systems are compared with those available in the literature and the effectiveness of the methods used are discussed.

Diet-Right: A Smart Food Recommendation System

  • Rehman, Faisal;Khalid, Osman;Haq, Nuhman ul;Khan, Atta ur Rehman;Bilal, Kashif;Madani, Sajjad A.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권6호
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    • pp.2910-2925
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    • 2017
  • Inadequate and inappropriate intake of food is known to cause various health issues and diseases. Due to lack of concise information about healthy diet, people have to rely on medicines instead of taking preventive measures in food intake. Due to diversity in food components and large number of dietary sources, it is challenging to perform real-time selection of diet patterns that must fulfill one's nutrition needs. Particularly, selection of proper diet is critical for patients suffering from various diseases. In this article, we highlight the issue of selection of proper diet that must fulfill patients' nutrition requirements. To address this issue, we present a cloud based food recommendation system, called Diet-Right, for dietary recommendations based on users' pathological reports. The model uses ant colony algorithm to generate optimal food list and recommends suitable foods according to the values of pathological reports. Diet-Right can play a vital role in controlling various diseases. The experimental results show that compared to single node execution, the convergence time of parallel execution on cloud is approximately 12 times lower. Moreover, adequate accuracy is attainable by increasing the number of ants.

Importance of PET/CT Scan Use in Planning Radiation Therapy for Lymphoma

  • Milana, Mitric-Askovic;Marko, Erak;Miroslav, Latinovic;Tihomir, Dugandzija
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권5호
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    • pp.2051-2054
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    • 2015
  • Background: Radiation therapy is a key part of the combined modality treatment for Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL), which can achieve locoregional control of disease. The 3D-conformal radiation oncology can be extended-field (EFRT), involved-field (IFRT) and involved node (INRT). New techniques have resulted in a smaller radiation field and lower dose for critical organs such as lung heart and breast. Materials and Methods: In our research, we made a virtual simulation for one patient who was treated in four different radiotherapeutic techniques: mantle field (MFRT), EFRT, IFRT and INRT. After delineatiion we compared dose-volume histograms for each technique. The fusion of CT for planning radiotherapy with the initial PET/CT was made using Softver Xio 4.6 in the Focal program. The dose for all four techniques was 36Gy. Results: Our results support the use of PET/CT in radiation therapy planning. With IFRT and INRT, the burden on the organs at risk is less than with MFRT and EFRT. On the other hand, the dose distribution in the target volume is much better with the latter. Conclusions: The aim of modern radiotherapy of HL and NHL is to reduce the intensity of treatment and therefore PET/CT should be used to reduce and not increase the amount of tissue receiving radiation.

A Component-Based Localization Algorithm for Sparse Sensor Networks Combining Angle and Distance Information

  • Zhang, Shigeng;Yan, Shuping;Hu, Weitao;Wang, Jianxin;Guo, Kehua
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권3호
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    • pp.1014-1034
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    • 2015
  • Location information of sensor nodes plays a critical role in many wireless sensor network (WSN) applications and protocols. Although many localization algorithms have been proposed in recent years, they usually target at dense networks and perform poorly in sparse networks. In this paper, we propose two component-based localization algorithms that can localize many more nodes in sparse networks than the state-of-the-art solution. We first develop the Basic Common nodes-based Localization Algorithm, namely BCLA, which uses both common nodes and measured distances between adjacent components to merge components. BCLA outperforms CALL, the state-of-the-art component-based localization algorithm that uses only distance measurements to merge components. In order to further improve the performance of BCLA, we further exploit the angular information among nodes to merge components, and propose the Component-based Localization with Angle and Distance information algorithm, namely CLAD. We prove the merging conditions for BCLA and CLAD, and evaluate their performance through extensive simulations. Simulations results show that, CLAD can locate more than 90 percent of nodes in a sparse network with average node degree 7.5, while CALL can locate only 78 percent of nodes in the same scenario.

Dendritic Cell-Mediated Mechanisms Triggered by LT-IIa-B5, a Mucosal Adjuvant Derived from a Type II Heat-Labile Enterotoxin of Escherichia coli

  • Lee, Chang Hoon;Hajishengallis, George;Connell, Terry D.
    • Journal of Microbiology and Biotechnology
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    • 제27권4호
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    • pp.709-717
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    • 2017
  • Mucosal tissues are the initial site through which most pathogens invade. As such, vaccines and adjuvants that modulate mucosal immune functions have emerged as important agents for disease prevention. Herein, we investigated the immunomodulatory mechanisms of the B subunit of Escherichia coli heat-labile enterotoxin type IIa ($LT-IIa-B_5$), a potent non-toxic mucosal adjuvant. Alternations in gene expression in response to $LT-IIa-B_5$ were identified using a genome-wide transcriptional microarray that focused on dendritic cells (DC), a type of cell that broadly orchestrates adaptive and innate immune responses. We found that $LT-IIa-B_5$ enhanced the homing capacity of DC into the lymph nodes and selectively regulated transcription of pro-inflammatory cytokines, chemokines, and cytokine receptors. These data are consistent with a model in which directional activation and differentiation of immune cells by $LT-IIa-B_5$ serve as a critical mechanism whereby this potent adjuvant amplifies mucosal immunity to co-administered antigens.

Maximizing Information Transmission for Energy Harvesting Sensor Networks by an Uneven Clustering Protocol and Energy Management

  • Ge, Yujia;Nan, Yurong;Chen, Yi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제14권4호
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    • pp.1419-1436
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    • 2020
  • For an energy harvesting sensor network, when the network lifetime is not the only primary goal, maximizing the network performance under environmental energy harvesting becomes a more critical issue. However, clustering protocols that aim at providing maximum information throughput have not been thoroughly explored in Energy Harvesting Wireless Sensor Networks (EH-WSNs). In this paper, clustering protocols are studied for maximizing the data transmission in the whole network. Based on a long short-term memory (LSTM) energy predictor and node energy consumption and supplement models, an uneven clustering protocol is proposed where the cluster head selection and cluster size control are thoroughly designed for this purpose. Simulations and results verify that the proposed scheme can outperform some classic schemes by having more data packets received by the cluster heads (CHs) and the base station (BS) under these energy constraints. The outcomes of this paper also provide some insights for choosing clustering routing protocols in EH-WSNs, by exploiting the factors such as uneven clustering size, number of clusters, multiple CHs, multihop routing strategy, and energy supplementing period.

풍하중을 받는 평면 막구조물의 동적불안정 판정에 관한 연구 (Study on Dynamic Instability of Plane Membrane Structures under Wind Action)

  • 한상을;후효무
    • 한국전산구조공학회논문집
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    • 제22권2호
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    • pp.145-152
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    • 2009
  • 본 논문에서는 풍하중을 받는 평면 막구조물의 동적불안정 판정을 규명하였다. 풍하중을 받는 막구조물의 지배방정식을 정식화할 경우 가장 중요한 것은 막 표면의 공기 압력을 합리적으로 산정하는 것이다. 베르누이 윈리에 의하여 유체 압력은 속도 퍼텐셜과 관계를 가지며 않은 날개 원리에 의해 막 표면 공기의 움직임을 일련의 와류로 간주하고 속도 퍼텐셜을 구할 수 있다. 이 논문에서는 가장 많이 쓰이는 3 절점 삼각형 막요소를 이용하여 가중 잔여치 갤러킨법을 적용한 안정 평가의 판별식을 유도하였다. 수치해석 모델로는 정사각형과 직사각형의 막구조물을 채택하였고 임계 풍속에 대한 초기인장력과 풍방향의 영향을 분석하였다.

자동차 엔진 크랭크축의 진동해석을 위한 자유도 저감법 개발에 관한 연구 (A Proposed Reduction Method for Vibatiton Analysis of Automobile Engine Crakshfts)

  • 최명진
    • 한국생산제조학회지
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    • 제5권2호
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    • pp.29-37
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    • 1996
  • High speed engines with high power are increasingly on demands and almost engines employ crankshafts Such problems as bending and torsional vibrations become the point at issue in crankshaft analysis and design. In this study to overcome the diffiiculty with the large amount of computation in finite element vibration analysis of a crankshaft, a reduction method based on influence coefficient and lumped parameter is presented. which reduces the computation amount effectively and can be used in vibrational analysis and design of any types of crankshafts Crank journal and pinparts are meodelled as elements with 6degrees of freedom per node. Crank web part is modelled using equivalent mass and stiffness matices . based up on lumped parameter and influence coefficient respectively to reduce total degrees of freedom considerablely. To confirm the scheme of the study the results are compared with the known data and they are coincident. Also a simple crankshaft is designed and manufactured for experiments. The calculated results using reduction method and the experimental results agree well The scheme of this study can be utilized in evaluation results agree well. The calculated result are compared with the known data and they are coincident. Also a simple crankshaft is designed and manufactured for experiments. The calculated results using reduction method and the experimental results agree well. The scheme of this study can be utilized in evaluation and development of high speed engine.

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확산화염의 진동불안성의 기원에 대해서 (On the Origin of Oscillatory Instabilities in Diffusion Flames)

  • 김종수
    • 한국연소학회지
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    • 제10권3호
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    • pp.25-33
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    • 2005
  • Fast-time instability is investigated for diffusion flames with Lewis numbers greater than unity by employing the numerical technique called the Evans function method. Since the time and length scales are those of the inner reactive-diffusive layer, the problem is equivalent to the instability problem for the $Li\tilde{n}\acute{a}n#s$ diffusion flame regime. The instability is primarily oscillatory, as seen from complex solution branches and can emerge prior to reaching the upper turning point of the S-curve, known as the $Li\tilde{n}\acute{a}n#s$ extinction condition. Depending on the Lewis number, the instability characteristics is found to be somewhat different. Below the critical Lewis number, $L_C$, the instability possesses primarily a pulsating nature in that the two real solution branches, existing for small wave numbers, merges at a finite wave number, at which a pair of complex conjugate solution branches bifurcate. For Lewis numbers greater than $L_C$, the solution branch for small reactant leakage is found to be purely complex with the maximum growth rate found at a finite wave number, thereby exhibiting a traveling nature. As the reactant leakage parameter is further increased, the instability characteristics turns into a pulsating type, similar to that for L < $L_C$.

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Adaptive Energy Optimization for Object Tracking in Wireless Sensor Network

  • Feng, Juan;Lian, Baowang;Zhao, Hongwei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권4호
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    • pp.1359-1375
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    • 2015
  • Energy efficiency is critical for Wireless Sensor Networks (WSNs) since sensor nodes usually have very limited energy supply from battery. Sleep scheduling and nodes cooperation are two of the most efficient methods to achieve energy conservation in WSNs. In this paper, we propose an adaptive energy optimization approach for target tracking applications, called Energy-Efficient Node Coordination (EENC), which is based on the grid structure. EENC provides an unambiguous calculation and analysis for optimal the nodes cooperation theoretically. In EENC, the sleep schedule of sensor nodes is locally synchronized and globally unsynchronized. Locally in each grid, the sleep schedule of all nodes is synchronized by the grid head, while globally the sleep schedule of each grid is independent and is determined by the proposed scheme. For dynamic sleep scheduling in tracking state we propose a multi-level coordination algorithm to find an optimal nodes cooperation of the network to maximize the energy conservation while preserving the tracking performance. Experimental results show that EENC can achieve energy saving of at least 38.2% compared to state-of-the-art approaches.