Approach to adaptive service matchmaking

To make service matchmaking more adaptive to various service requests and diverse web services, an adaptive approach-ASMA is proposed to service matchmaking based on temporal logic model-checking. The approach is based on the proposed abstract service model, ASM-TL, which addresses some important constraints for identifying capabilities of web services, such as service inner constraints and invocation constraints, and also has a virtual process model for describing service behavioral properties. By treating service requests as temporal logic conditions and web services as temporal models, ASMA does service matchmaking through model checking. Therefore, ASMA makes service matchmaking more accurate and more adaptive to the variety of service requests and the diversity of web services. The approach has been applied to the problem solving environment （PSE） for bioinformatics research. Applications show that the approach is suitable for dynamic environments.

共创海运业之荣景

海运业在经历了亚洲金融风暴的冲击后,过去的一年也经历了繁荣的成长复生,甘甜苦辣俱都尝遍。随着近年来大型船舶及合并联盟的发展,如何在剧烈竞争的环境中存续并获致合理的报酬回收,仍是业界的主要课题。 在公元2000年的千禧新岁中,谨祝福大家新春快乐、吉祥如意、富贵昌隆,并就下列观点分享我们对於未来航运发展的看法,并请不吝赐教,共创海运业之荣景。

A New Carbon and Oxygen Balance Model Based on Ecological Service of Urban Vegetation

The application of human induced oxygen consumption and carbon emission theory in urban region was summed up and on this base a new model of urban carbon and oxygen balance (UCOB) was constructed by calculating the carbon and oxygen fluxes. The purpose was to highlight the role of vegetation in urban ecosystems and evaluate the effects of various human activities on urban annual oxygen consumption and carbon emission. Hopefully,the model would be helpful in theory to keep the regional balance of carbon and oxygen,and provide guidance and support for urban vegetation planning in the future. To test the UCOB model,the Jimei District of Xiamen City,Fujian Province,China,a very typical urban region,was selected as a case study. The results turn out that Jimei′s vegetation service in oxygen emission and carbon sequestration could not meet the demand of the urban population,and more than 31.49 times of vegetation area should be added to meet the whole oxygen consumption in Jimei while 9.60 times of vegetation area are needed to meet the carbon sequestration targets. The results show that the new UCOB model is of a great potential to be applied to quantitative planning of urban vegetation and regional eco-compensation mechanisms.

Single Server Queueing Models and Birth-Death Process

A transition diagram is used to describe the behavior of systems. Birth-death equations were derived from transition diagram depicting the state of the birth-death processes. Queue models and characteristics of queue models are also derivable from birth-death processes. These queue models consist of mathematical formulas and relationships that can be used to determine the operating characteristics （performance measures） for a waiting line. Schematic and transition diagrams of different single server queue models were shown. Relationships between birth-death processes, waiting lines （queues） and transition diagrams were given. While M/M/I/K queue model states was limited by K customers and had （K＋I） states, M/M/1/1 queue model had only two states. M/G/1/∝/∝ and M/M/1/∝/∝ shared similar characteristics. Many ideal queuing situations employ M/M/1 queueing model.

Modelling Ecosystem Water Supply Services across the Lancang River Basin

Ecosystem services related to water supply are now a hot topic in ecology and hydrology. Here, water supply service in the Lancang River basin was evaluated using the newly developed model InVEST. We found the mean annual water supply in Lancang River basin is approximately 7.24E＋10 m3 y-1 with 23.87% from main stream and 76.13% from the tributaries. There is an increasing trend downstream. Grasslands and forests contribute 71.66% of the total water. A comparison of water supply capacity per unit area for ecosystems of different composition indicates that there is a decreasing trend from broad- leafed forest, mixed coniferous and broad-leafed forest, bamboo forest, coniferous forest, shrub forest and grassland. Two-thirds of the total water is provided by an area covering 40% of the total basin area. This study provides guidelines for the efficient management of water resources in the Lancang River basin.

Evaluation of Inner Mongolia Wind Erosion Prevention Service based on Land Use and the RWEQ Model

Inner Mongolia is the important ecological barrier zone in northern China,which plays an important role in the prevention and control of wind in the regional ecosystem.Based on the Revised Wind Erosion Equation(RWEQ)model and the cost-recovery method,this study simulated the wind erosion prevention service(WEPS)in Inner Mongolia in 2010 and 2015,investigated the spatial pattern of material and monetary value of WEPS,and analyzed the differences among various cities and various ecosystems.The results indicated that the total WEPS of Inner Mongolia was estimated to be 73.87×10^(8) t in 2015,which was 4.61×10^(8) t less than in 2010,while the monetary value of WEPS was calculated to be 738.66×10^(8) yuan in 2015,which was 46.16×10^(8) yuan less than in 2010.Among all the leagues and cities,Xilin Gol League supported the highest WEPS,reaching 18.65×10^(8) t in 2015,while Wuhai provided the lowest.The WEPS of Hulunbeier increased the most,by 4.37×10^(8) t from 2010 to 2015.The WEPS in the grassland ecosystem was the highest among the different ecosystems,accounting for more than55%of the total WEPS in Inner Mongolia,but it was reduced by 1.05×10^(8) t during the same period.The WEPS in the forest ecosystem increased the most,reaching 0.19×10^(8) t.This study found that the implementation of projects such as returning farmland to forests and grasses and sand control effectively increased the WEPS by increasing the forest area.However,unsuitable land use increased the desertification of ecosystems which resulted in a reduction of WEPS in Inner Mongolia.

A DISCRETE-TIME Geo/G/1 RETRIAL QUEUE WITH J-VACATION POLICY AND GENERAL RETRIAL TIMES

The authors discuss a discrete-time Geo/G/1 retrial queue with J-vacation policy and general retrial times.As soon as the orbit is empty,the server takes a vacation.However,the server is allowed to take a maximum number J of vacations,if the system remains empty after the end of a vacation.If there is at least one customer in the orbit at the end of a vacation,the server begins to serve the new arrivals or the arriving customers from the orbit.For this model,the authors focus on the steady-state analysis for the considered queueing system.Firstly,the authors obtain the generating functions of the number of customers in the orbit and in the system.Then,the authors obtain the closed-form expressions of some performance measures of the system and also give a stochastic decomposition result for the system size.Besides,the relationship between this discrete-time model and the corresponding continuous-time model is also investigated.Finally,some numerical results are provided.

Ontology-Driven Discovering Model for Geographical Information Services

This paper proposes an ontology-driven discovering model for the geographical information services to improve their recall ratio and precision ratio. This model uses the geographical information service ontology. In this paper, first we study the multilevel matching arithmetic of geographical information services. This arithmetic is used for filtering and matching the services in the service register center according to the similarity between services selected and services requested from the definition of the function similarity and credit standing similarity. The matching arithmetic, geographical information service ontology and semantic description constitute the discovering model. Finally, we test and analyze the model from the recall ratio, precision ratio, responsivity and load balance. The result indicates that the ontology-driven discovering model is excellent in recall ratio and precision ratio, and can maintain the dynamic load balance of service copy.