scholarly journals Optimal Pricing of Spectrum Resources in Wireless Opportunistic Access

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Hanna Bogucka
Keyword(s):  
Optimal Taxation ◽  
Mathematical Formulation ◽  
The Other ◽  
Channel State ◽  
Network Nodes ◽  
Opportunistic Access ◽  
Cognitive Wireless Networks ◽  
Taxation Rate ◽  
Optimization Simulation ◽  
Available Resources

We consider opportunistic access to spectrum resources in cognitive wireless networks. The users equipment, or the network nodes in general are able to sense the spectrum and adopt a subset of available resources (the spectrum and the power) individually and independently in a distributed manner, that is, based on their local channel quality information and not knowing the Channel State Information (CSI) of the other nodes' links in the considered network area. In such a network scenery, the competition of nodes for available resources is observed, which can be modeled as a game. To obtain spectrally efficient and fair spectrum allocation in this competitive environment with the nodes having no information on the other players, taxation of resources is applied to coerce desired behavior of the competitors. In the paper, we present mathematical formulation of the problem of finding the optimal taxation rate (common for all nodes) and propose a reduced-complexity algorithm for this optimization. Simulation results for these derived optimal values in various scenarios are also provided.

Discussion of the Oblique Rotator Model Cases Of 108 Aqr and x Serp.

1976 ◽  
Vol 32 ◽  
pp. 577-588
Author(s):  
C. Mégessier ◽  
V. Khokhlova ◽  
T. Ryabchikova
Keyword(s):  
Mathematical Formulation ◽  
The Other ◽  
Rotator Model ◽  
Oblique Rotator ◽  
First Results

My talk will be on the oblique rotator model which was first proposed by Stibbs (1950), and since received success and further developments. I shall present two different attempts at describing a star according to this model and the first results obtained in the framework of a Russian-French collaboration in order to test the precision of the two methods. The aim is to give the best possible representation of the element distributions on the Ap stellar surfaces. The first method is the mathematical formulation proposed by Deutsch (1958-1970) and applied by Deutsch (1958) to HD 125248, by Pyper (1969) to α2CVn and by Mégessier (1975) to 108 Aqr. The other one was proposed by Khokhlova (1974) and used by her group.

A study of in-patients aged 60 years and over treated in the Department of Plastic Surgery, Dundee Royal Infirmary, in 1983

1985 ◽  
Vol 71 (3) ◽  
pp. 171-175
Author(s):  
C. D. T. Low
Keyword(s):  
Health Service ◽  
Elderly Patients ◽  
Plastic Surgery ◽  
Special Problem ◽  
The Other ◽  
Special Consideration ◽  
Direct Result ◽  
Royal Infirmary ◽  
Delayed Healing ◽  
Available Resources

SummaryThis study was conducted to determine the extent to which elderly patients constitute a special problem in plastic surgery. In 1983 patients aged 60 years and over accounted for 3 7% of all admissions to the plastic surgery ward at the Dundee Royal Infirmary and 52% of all patient-days there; they tended to stay longer than other patients and cost the Health Service more than £130000. About one-third of admissions were as a direct result of accidents; of the other two-thirds, the majority was for the treatment of malignancies. In the study, special consideration was given to delayed healing after surgery and other problems arising while these patients were in hospital, and the reasons for prolonged stays. The study confirms that there is a problem which is stretching available resources.

The Algorithmic Aspects of Creating and Using Wireless Sensor Network Key Spaces Based on Combinatorial Block Diagrams

Vestnik MEI ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 108-118
Author(s):  
Aleksandr B. Frolov ◽  
◽  
Natalya P. Kochetova ◽  
Anton O. Klyagin ◽  
Dmitriy Yu. Temnikov ◽  
...  
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Block Diagram ◽  
The Other ◽  
Wireless Sensor ◽  
Algorithmic Approach ◽  
Network Nodes ◽  
Rule Sets ◽  
Independent Calculation ◽  
Do So

Algorithmic approach principles relating to development and use of wireless sensor network (WSS) key spaces are formulated based on an analysis of the keys management peculiarities. The formulated principles, which meet certain requirements for the WSS key spaces, have been elaborated proceeding from the assumption that their structure corresponds to one of the varieties of combinatorial block diagrams: cyclic or acyclic projective plane, linear or quadratic transversal block diagrams. Owing to the WSS having a distributed configuration, it becomes possible to avoid the need to construct a combinatorial block diagram in full scope, and the required blocks are computed, whenever necessary, in scaling the network (in adding new nodes) or when determining, in a decentralized manner, the switching parameters of specific nodes. To do so, it is necessary to have algorithms for computing the blocks of the combinatorial block diagram (as the sets of key numbers allocated to a given node) and dual blocks (as the sets of the numbers of nodes to which keys are assigned with the numbers coinciding with the numbers of dual blocks), as well as algorithms for solving derived problems: computing of the key numbers common to two nodes and the number of the node that has a common key with one of two nodes and, possibly, another key with the other one. These problems are solved by using the numbering of elements, blocks and dual blocks in accordance with the proposed duality rule: sets of elements and dual blocks are in one-to-one correspondence by numbering; the dual block with a specified number contains the numbers of blocks containing elements with this number. Distributed (independent) calculation of blocks is carried out on the basis of algebraic identifiers computed by block numbers. In addition to the possible absence of a physical connection between the nodes, the inadmissibility of using separate (compromised) keys is taken into account, and the incomplete furnishing of the network nodes with keys, as well as the incompleteness of the system implementation as a whole. Algorithms for computing the switching parameters of two nodes in designing the WSS and an algorithm for computer modeling of the calculation of such parameters during the WSS operation subject to the specified constraints and in using any of the above types of combinatorial block diagrams are presented.

scholarly journals Optimization of information exchange in networks under conditions of uncertainty

2020 ◽  
Vol 69 (4) ◽  
Author(s):  
O. V. Senkov ◽  
Keyword(s):  
Information Exchange ◽  
Process Management ◽  
Telecommunication Network ◽  
Point Of View ◽  
The Other ◽  
Network Nodes ◽  
Exchange Of Information ◽  
Linear Convolution ◽  
First Case ◽  
Isolated Points

The article considers the problem of optimizing the exchange of information in the conditions of uncertainty that arises in the process of functioning of converged networks. The uncertainties formulated in the paper are characterized by discrepancies in the "interests" of different network nodes, varying degrees of awareness or incomplete data on the value of system parameters. Such uncertainties lead to a decentralized process management strategy in a converged network. The problem of interaction of network nodes is considered from the point of view of game theory, at the same time players act as separate nodes of system, the exchange of information between which is limited by conditions of uncertainty. Decision-making procedures are formulated for the following cases: when one node is the center and the other opposes it and the center knows information about the choice of the second player; when the center does not know the capabilities of the second player, and the uncertainty lies in the random nature of the strategy of the second player; network node synergy model. For the first case, the optimal control is based on the maximum action of the first station (center) and the maximum resistance of the other station (second player) and can use the maximum model. For the second case, the limitations of the strategy of the game (including the strategy of punishment of the player) are determined and it is proved that the gain, more than the maximum guaranteed result of the center, cannot be obtained on any other class of strategies. The relation of the center to the uncertainty in the model based on the synergetic concept of the operation of convergent networks is such that it seeks to maximize the linear convolution of the values of its criterion. The peculiarities of constructing a strategy for the exchange of information between individual nodes of the network in the presence and absence of isolated points in the set of choices of the player who opposes the center are studied. The developed model of interaction of heterogeneous subsystems of the telecommunication network in the conditions of uncertainty can be used for situations when nodes have incomplete information about both the system as whole and other nodes.

scholarly journals Cross-Layer Throughput Optimization in Cognitive Radio Networks with SINR Constraints

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Miao Ma ◽  
Danny H. K. Tsang
Keyword(s):  
Cognitive Radio ◽  
Mathematical Formulation ◽  
Heuristic Method ◽  
Global Optimum ◽  
Mixed Integer ◽  
Cross Layer ◽  
Throughput Optimization ◽  
Radio Interference ◽  
Secondary Users ◽  
Optimization Simulation

Recently, there have been some research works in the design of cross-layer protocols for cognitive radio (CR) networks, where the Protocol Model is used to model the radio interference. In this paper we consider a multihop multi-channel CR network. We use a more realisticSignal-to-Interference-plus-Noise Ratio (SINR)model for radio interference and study the following cross-layer throughput optimization problem: (1) Given a set of secondary users with random but fixed location, and a set of traffic flows, what is the max-min achievable throughput? (2) To achieve the optimum, how to choose the set of active links, how to assign the channels to each active link, and how to route the flows? To the end, we present a formal mathematical formulation with the objective of maximizing the minimum end-to-end flow throughput. Since the formulation is in the forms ofmixed integer nonlinear programming (MINLP), which is generally a hard problem, we develop a heuristic method by solving a relaxation of the original problem, followed by rounding and simple local optimization. Simulation results show that the heuristic approach performs very well, that is, the solutions obtained by the heuristic are very close to the global optimum obtained via LINGO.

scholarly journals Penerapan Good Governance di Indonesia dalam Tinjauan Hukum Islam Kontemporer

2017 ◽  
Vol 7 (1) ◽  
pp. 163-187
Author(s):  
Muhammad Solikhudin
Keyword(s):  
Islamic Law ◽  
Good Governance ◽  
Legal Discourse ◽  
The State ◽  
The Other ◽  
Social Culture ◽  
Human Welfare ◽  
Abuse Of Power ◽  
Other Hand ◽  
Available Resources

Abstract: This article analyzes the concept of good governance from the perspective of contemporary thought of Islamic law. Good governance is a new concept in islamic legal discourse, but an important one for preventing abuse of power. Good governance is understood to be applied in government and bureaucracy. Clean government should be effective, efficient, transparent, honest and accountable. This can be executed by using all available resources (human, social, culture, politics and economy) for the welfare of the community. Because of this noble goal, good governance is a must, from the perspective of Islamic law. The effort to realize welfare for the community by the state is in line with Islamic law. On the other hand, there is arguably no corresponding textual references from al-Qur’an or Hadith on the issue of good governance. Therefore the concept of mashlahah mursalah is employed since it highly built upon the accommodation of human welfare as it is the main mission of Islam.  Abstrak: Tulisan ini menguraikan upaya good governance dengan sudut pandang hukum Islam kontemporer. Good governance merupakan gerakan ijtihâdiyyah dalam mewujudkan pemerintahan yang baik untuk menegasikan penyalahgunaan kekuasaan yang terjadi di dunia, khususnya di Indonesia. Good governance diartikan sebagai tata kelola pemerintahan yang bersih dan baik. Pemerintahan yang bersih adalah pemerintahan yang efektif, efisien, transparan, jujur, dan bertanggung jawab, sedangkan pemerintahan yang baik adalah pemerintahan negara yang berkaitan dengan sumber sosial, budaya, politik, serta ekonomi diatur sesuai dengan kekuasaan yang dilaksanakan pada masyarakat. Berdasarkan hukum Islam kontemporer, penerapan good governance di Indonesia harus dilakukan. Metode pencapaian kesejahteraan dalam bernegara dengan berbagai pemasalahan kontemporer yang timbul menyertainya harus disikapi secara hukum. Di sisi lain, secara tekstual, nas-nas syariat tidak menyikapi semua permasalahan yang timbul tersebut secara spesifik, maka mashlahah mursalah dapat dipertimbangkan sebagai salah satu metode ijtihad kontemporer untuk mengakomodasi kemaslahatan manusia dalam penerapan good governance, karena Islam datang sebagai rahmat bagi alam semesta.

scholarly journals Choosing optimal node roles in a multi-gateway wireless ad hoc network

2020 ◽  
pp. 30-30
Author(s):  
Andrew Makhorin ◽  
Maxim Terentiev
Keyword(s):  
Ad Hoc Network ◽  
Ad Hoc ◽  
Mathematical Formulation ◽  
Mixed Integer ◽  
Wireless Ad Hoc Network ◽  
Network Simulator ◽  
Network Nodes ◽  
Second Stage ◽  
Mip Model ◽  
Optimal Node

This article considers a problem to choose parameters of a procedure for changing node roles in a multi-gateway wireless ad hoc network used in aerospace systems. Mathematical formulation of a mixed-integer programming (MIP) model to optimize the changing-node-role-procedure parameters is proposed, where the attention is focused on appropriate parameterization in order to make it possible to include additional constraints, if necessary. A practical two-stage technique used by the authors to solve the considered problem is briey discussed. On the first stage, the branch-and-bound algorithm, provided with cutting plane constraints of some classes, is applied to choose optimal roles of the network nodes. On the second stage, the network simulator developed by the authors is used to estimate main characteristics of the resulting network. Workability of the proposed approach is demonstrated by results of computational experiments.

Methods for Dependability and Security Analysis of Large Networks

2009 ◽  
pp. 921-929
Author(s):  
Ioannis Chochliouros ◽  
Anastasia S. Spiliopoulou ◽  
Stergios P. Chochliouros
Keyword(s):  
Experimental Data ◽  
Formal Methods ◽  
Security Analysis ◽  
The Other ◽  
Network Nodes ◽  
Dependability Analysis ◽  
Underlying Network ◽  
Security Properties ◽  
Unauthorized Disclosure ◽  
Specific Evaluation

Dependability and security are rigorously related concepts that, however, differ for the specific proprieties they mainly concentrate on. In particular, in most commonly applied cases found in practical design techniques (Piedad & Hawkins, 2000), the dependability concept usually includes the security one, being a superset of it. In typical cases, security mainly comprises the following fundamental characteristics: confidentiality, integrity, and availability. Indeed, dependability mainly encompasses the following attributes (Avizienis, Laprie, Randell, & Landwehr, 2004): (1) availability: readiness for correct service; (2) reliability: continuity of correct service; (3) safety: absence of catastrophic consequences on the user(s) and the environment; (4) confidentiality: absence of unauthorized disclosure of information; (5) integrity: absence of improper system alterations; and (6) maintainability: ability to undergo modifications and repairs. The present work primarily intends to deal with formal methods, appropriate to perform both security and dependability analysis in modern networks. In general, security analysis of great networks takes the form of determining the exploitable vulnerabilities of a network, and intends to provide results or appropriate informative (or occasionally experimental) data about which network nodes can be compromised by exploiting chains of vulnerabilities, as well as specifying which fundamental security properties are altered (e.g., Confidentiality, Integrity, Availability). Therefore, such type of analysis is also referred as “network vulnerability analysis.” On the other hand, dependability analysis of networks typically intends to determine specific dependencies within the nodes (or the services offered) of the (appropriate) underlying network, so as to provide results about the consequences of (potential) faults (on services or hosts) and to find out which among these faults are able to cause unacceptable consequences, in terms of the basic dependability attributes. At this specific evaluation, it should be noted that it is possible to consider attacks (as well as attack consequences) as faults.

scholarly journals Unified Scale Theorem: A Mathematical Formulation of Scale in the Frame of Earth Observation Image Classification

2021 ◽  
Vol 5 (3) ◽  
pp. 127
Author(s):  
Christos G. Karydas
Keyword(s):  
Image Classification ◽  
Fractal Analysis ◽  
Mathematical Formulation ◽  
Earth Observation ◽  
The Other ◽  
Land Uses ◽  
Scale Selection ◽  
Broad Area ◽  
Selection For ◽  
Sentinel 2

In this research, the geographic, observational, functional, and cartographic scale is unified into a single mathematical formulation for the purposes of earth observation image classification. Fractal analysis is used to define functional scales, which then are linked to the other concepts of scale using common equations and conditions. The proposed formulation is called Unified Scale Theorem (UST), and was assessed with Sentinel-2 image covering a variety of land uses from the broad area of Thessaloniki, Greece. Provided as an interactive excel spreadsheet, UST promotes objectivity, rapidity, and accuracy, thus facilitating optimal scale selection for image classification purposes.

scholarly journals Realizing the promise of robotic self-x systems

Robotica ◽  
2011 ◽  
Vol 29 (1) ◽  
pp. i-ii
Author(s):  
Amor A. Menezes ◽  
Pierre T. Kabamba
Keyword(s):  
Dynamic Environment ◽  
The Other ◽  
Warning Signals ◽  
Replication Process ◽  
Compact Structure ◽  
Insurmountable Obstacle ◽  
Self Replication ◽  
Available Resources ◽  
Sensor Suite

Consider a robot trying to accomplish a mission in an unfamiliar, hostile, and dynamic environment. As the robot encounters a seemingly insurmountable obstacle, it quickly reconfigures itself into two smaller robots, and with the aid of a nearby puddle of water, these two robots conduct self-detection procedures to confirm successful reconfiguration. One robot then calibrates itself using its reduced sensor suite and begins climbing over the obstacle, whilst the other robot folds itself into a compact structure and finds a crevice it can use to bypass the obstacle. But when the obstacle shifts, both robots send signals to a base to warn of impending mission failure. A copy of the original robot, located at the base, receives these warning signals and initiates a rapid self-replication process by assembling available resources. The resultant robotic offspring are then ready to continue the mission when called upon.

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