检索结果-南通市图书馆

Competitive Resource Allocation Among Urban Congestion Areas in a Modern Big City

在线全文

学校读者我要写书评

暂无评论

Journal of the Operations Research Society of China 2024年第1期12卷 133-153页

作者： alexander Krylatov Anastasiya Raevskaya Institute of Applied Mathematical Research of the Karelian Research Centre of the Russian Academy of Sciences Petrozavodsk185910Russia Saint Petersburg State University Saint Petersburg199034Russia

The continuing growth of modern big cities leads to their spatial expansion and the emergence of new road connections and urban *** where large transportation flows of pedestrians,passengers,and drivers come together create demand points,which attract business companies that strive to allocate their resources in the most sought-after ***,the law of supply and demand restrains companies from allocating all their resources solely in the most popular congestion areas since the more valuable an urban area,the higher the cost to be paid for a resource unit allocation *** a result,companies act in a non-cooperative manner and try to minimize their own overall costs when allocating resources across available commercial areas in a big ***-cooperative behavior of companies leads to the problem of Nash equilibrium search in the game of competing *** this paper,we study the corresponding resource allocation game under affine cost functions and obtain Nash equilibrium strategies in explicit *** findings allow us to develop a simple procedure for computing Nash equilibria in the game of companies allocating their resources among urban congestion *** computational study demonstrates the dependence of the average price for resource allocation on the number of players and their resource *** outcome of the paper contributes to flow theory and seems to be fresh and useful for managers.

关键词： Resource allocation Nash equilibrium Affine costs

Analysis of the X-ray emission from OB stars Ⅲ: low-resolution spectra of OB stars

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2020年第7期20卷 161-171页

作者： Elizaveta Ryspaeva alexander Kholtygin Crimean Astrophysical Observatory NauchnyCrimea 298409Russia Saint-Petersburg State University Saint-Petersburg 198504Russia Institute of Astronomy Russian Academy of Sciencesul.Pyatniskaya 48Moscow 119017Russia

This paper is the third in our series of papers devoted to the investigation of X-ray emission from OB *** our two previous papers,we study the high-resolution X-ray spectra of 32 O stars and 25 B stars to investigate the correlations between the properties of X-ray emission and stellar *** checked if the X-ray hardness and post-shock plasma temperature grow with increasing stellar magnetic field,mass loss rate and terminal wind *** previous analysis of high-resolution spectra showed that the correlations are weak or even *** the present paper,we analyzed low-resolution X-ray spectra,using model-independent X-ray hardness values for checking the above mentioned *** establish that X-ray luminosities LX weakly depend on the stellar magnetic *** the same time,Lx ∝ M0.5 and LX ∝ Ekin0.5,where M is the mass loss rate and Ekin is the kinetic energy of the *** X-ray luminosities decrease with growing magnetic confinement parameter η.We also argue that there is an additional(probably non-thermal) component contributed to the stellar X-ray emission.

关键词： stars:early-type stars:spectra:X-Ray

The Investigation of the Dynamical Evolution of Extrasolar Three-planetary System GJ 3138

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2022年第1期22卷 68-84页

作者： alexander Perminov Eduard Kuznetsov Ural Federal University 51 Lenin AvenueYekaterinburgRussia

This article is devoted to studying the dynamical evolution and orbital stability of compact extrasolar threeplanetary system GJ 3138. In this system, all semimajor axes are less than 0.7 au. The modeling of planetary motion is performed using the averaged semi-analytical motion theory of the second order in planetary masses,which the authors construct. Unknown and known with errors orbital elements vary in allowable limits to obtain a set of initial conditions. Each of these initial conditions is applied for the modeling of planetary motion. The assumption about the stability of observed planetary systems allows to eliminate the initial conditions leading to excessive growth of the orbital eccentricities and inclinations and to identify those under which these orbital elements conserve moderate values over the whole modeling interval. Thus, it becomes possible to limit the range of possible values of unknown orbital elements and determine their most probable values in terms of stability.

关键词： Planetary Systems planets and satellites:dynamical evolution and stability planetstar interactions celestial mechanics

Planning to Plan-Integrating Control Flow

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2003年第1期8卷 1-7页

作者： alexander Nareyek Computer Science Department Carnegie Mellon University

In many planning situations, computation itself becomes a resource to be planned and scheduled. We model such computational resources as conventional resources which are used by control-flow actions, e.g., to direct the planning process. Control-flow actions and conventional actions are planned/scheduled in an integrated way and can interact with each other. Control-flow actions are then executed by the planning engine itself. The approach is illustrated by examples, e.g., for hierarchical planning, in which tasks that are temporally still far away impose only rough constraints on the current schedule, and control-flow tasks ensure that these tasks are refined as they approach the current time. Using the same mechanism, anytime algorithms can change appropriate search methods or parameters over time, and problems like scheduling critical time-outs for garbage collection can be made part of the planning itself.

关键词： meta-planning resource-bounded reasoning online planning integrated planning, sensing and execution integrated planning and scheduling hierarchical planning anytime algorithms local search metaheuristics

Common Criteria for the Assessment of Critical Infrastructures

在线全文

学校读者我要写书评

暂无评论

International Journal of Disaster Risk Science 2011年第1期2卷 15-24页

作者： alexander Fekete Federal Office of Civil Protection and Disaster Assistance 53008 BonnGermany

Society is reliant on infrastructure services, such as information and communication technology, energy, water, and food supply, but also on governmental, cultural, and search and rescue organizations. The goal of project KritisKAT at the Federal Office of Civil Protection and Disaster Assistance in Germany is the development of generic criteria for the identification and evaluation of infrastructures regarded as “critical” for society. Acknowledging that full protection against all threats and cascading effects is not possible, the approach focuses on the impacts rather than the prevention of threats. The development of generic criteria requires the prioritization of infrastructures and identification of their key characteristics for civil protection purposes, risk management activities, and strategic proactive planning. For this purpose, the development of a national critical infrastructure priority inventory is based on a thorough examination of the range of criteria typically used in similar approaches. The specific focus of this paper is to identify and simplify essential characteristics of infrastructure criticality. The main outcome of this study is the development of common criteria generally applicable to a variety of infrastructures.

关键词： prevention typically services

Evaluation and management of the child with hypothyroidism

在线全文

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2019年第2期15卷 124-134页

作者： alexander K.C.Leung alexander A.C.Leung Department of Pediatrics The University of Calgaryand The Alberta Children's Hospital#200233-16th Avenue NWCalgaryAB T2M 0H5Canada Department of Medicine The University of CalgaryCalgaryABCanada

Background Thyroid hormones are critical for early neurocognitive development as well as growth and development throughout *** recognition and treatment of hypothyroidism is,therefore,of utmost importance to optimize physical and neurodevelopmental *** sources A PubMed search was completed in Clinical Queries using the key terms 'hypothyroidism'.Results Hypothyroidism may be present at birth (congenital hypothyroidism) or develop later in life (acquired hypothyroidism).Thyroid dysgenesis and dyshormonogenesis account for approximately 85% and 15% of permanent cases of congenital primary hypothyroidism,*** than 95% of infants with congenital hypothyroidism have few,if any,clinical manifestations of *** screening programs allow early detection of congenital *** developed countries,Hashimoto thyroiditis is the most common cause of goiter and acquired hypothyroidism in children and ***,iodine deficiency associated with goiter is the most common cause of *** hypothyroidism is uncommon and may be associated with other congenital syndromes and deficiencies of other pituitary *** of the clinical features would allow prompt diagnosis and institution of *** To optimize neurocognitive outcome in infants with congenital hypothyroidism,treatment with levothyroxine should be started as soon as possible,preferably within the first 2 weeks of *** with acquired hypothyroidism should also be treated early to ensure normal growth and development as well as cognitive *** target is to keep serum TSH < 5 mIU/L and to maintain serum free T4 or total T4 within the upper half of the age-specific reference range,with elimination of all symptoms and signs of hypothyroidism.

关键词： Dysgenesis Dyshormonogenesis Hashimoto thyroiditis Hypothyroidism Iodine deficiency Levothyroxine Mental retardation Stunted growth

The significance of total carbon in greensand systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2009年第3期6卷 247-254页

作者： alexander Brown Fellow of the Institute of Cast Metal Engineers Penistone Sheffield S36 9QU England

The need for control of raw materials is critical to the success of iron casting production from greensand systems. The base silica sand is often overlooked with the main focus on bentonite additions. Carbonaceous additives can be considered a "necessary evil" to ensure a good surface finish and reduction in sand related surface defects. Other additives are used when systems get out of balance and these in turn add further to the complex nature of greensand systems. For castings requiring cores this becomes a bigger issue as many differing resin systems are employed for core production and these must be taken into consideration when controlling both the carbonaceous levels and the overall grading of the sand system. The twin effects on additional carbon and loss-on-ignition and overall sand grading need careful understanding and control. Various control methods are examined including traditional methods such as volatiles and loss-on-ignition along with bentonite determination methods and grading methods. Newer control methods such as total carbon are reviewed along with the overall package of testing and control *** predictive methods are looked at as a control feature as well. The quality of additives and their role and more importantly their interaction is highlighted,as this is an area often neglected as foundrymen battle for success in consistent quality castings. Suggested in-coming control tests are discussed allied to additions at the mixer. Also reviewed is the interpretation of results and the action required to ensure control and more importantly consistent quality castings from greensand systems with the emphasis on the understanding and control of carbonaceous additive on casting performance.

关键词： graded coal bentonite greensand total carbon volatiles

Testing and modelling of transient adhesion phenomena in rolling-sliding contacts

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第5期12卷 1016-1027页

作者： Daniel KVARDA alexander MEIERHOFER Klaus SIX Faculty of Mechanical Engineering Brno University of TechnologyBrno61669Czech Republic Virtual Vehicle Research GmbH Graz8010Austria

Transient adhesion effects in rolling–sliding contacts influence all aspects of train–track *** is of high importance specifically when these effects result in critically low adhesion,which poses a risk to traction and braking of railway *** study presents a model that can replicate the transient changes of the coefficient of adhesion with tested water and solid particle *** experimental data for the model are measured using a commercial ball-on-disc *** experimental results showed a liquid reservoir in front of the contact area that slowly reduces in *** observation was used in the modelling approach to divide the calculation into two stages where the reservoir is present and when it *** model was able to reproduce the occurrence of low adhesion region seen in experimental results with different particle concentrations.

关键词： coefficient of adhesion tribology transient effects wheel-rail contact

Prediction of ball-on-plate friction and wear by ANN with data-driven optimization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第6期12卷 1235-1249页

作者： alexander KOVALEV Yu TIAN Yonggang MENG State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

For training artificial neural network(ANN),big data either generated by machine or measured from experiments are used as input to"learn"the unspecified functions defining the *** experimental data are fed directly into the optimizer allowing training to be performed according to a predefined loss *** predict sliding friction and wear at mixed lubrication conditions,in this study a specific ANN structure was so designed that deep learning algorithms and data-driven optimization models can be *** ball-on-plate friction and wear data were analyzed using the specific training procedure to optimize the weights and biases incorporated into the neural layers of the ANN,and only two independent experimental data sets were used during the ANN optimization *** the training procedure,the ANN is capable to predict the contact and hydrodynamic pressure by adapting the output data according to the tribological condition implemented in the optimization algorithm.

关键词： machine learning deep learning artificial neural network mixed lubrication