基于生态系统服务价值的新疆后备土地资源质量评价

由于人口激增、气候变暖等因素导致的环境恶化、资源短缺及其各种影响成为当今研究的重点．土地资源的有限性对人类的生存和发展产生了制约作用，更加成为研究的热点之一．为了解决土地制约的问题，必须客观地对土地资源做出评价．利用新疆土地调查资料，以新疆土地资源的利用变化图，估算生态系统服务价值（ESV），总VES为7．13×10^8元．其中：农田VES为0．31×10^8元；林地VES为1．27×10^8元；草地VES为3．29×10^8元；水体VES为1．89×10^8元；未利用土地VES为0．37×10^8元．     

A new green index as an overall quantitative green performance indicator of a facility

Green assessment tools such as the Building Research Establishment Environmental Assessment Method, Leadership in Energy and Environmental Design, Comprehensive Assessment System for Building Environmental Efficiency, GREEN STAR and HK-BEAM have been used worldwide. These tools, which utilise qualitative, credit-based rating system have several limitations. Firstly, they can only provide a relative measure of the greenness of a facility. Secondly, there is the possibility that the ratings assigned may differ from one user to another depending on the needs and priorities of an organisation, a country, or a region. Several studies have also highlighted that such credit-based systems involve piece-meal (Zuo and Zhou in Renew Sustain Energy Rev 30:271–281, 2014), as opposed to integrated evaluation of the green criteria, and the greenness of a facility. This paper proposes a new Green Index (GI) as a tool for assessing the level of greenness of a facility that overcomes the aforementioned limitations. The use of stock market composite index as a basis for the GI development has enabled an established tool for assessing stock market performances to progress into the domain of industrial and commercial facility management. Development of the GI involves two steps, namely the development of a weighting scheme using the factor analysis approach, followed by the composite GI formulation that is based on the stock market composite index. The developed Green Index is based on quantitative analysis and measurement of parameters, and hence, reflect the actual measure of the overall impact of a facility on the environment. With only a single indicator to represent multiple green elements, it makes it easier for facility managers to effectively and quantitatively monitor, analyse, compare and benchmark the actual level of greenness of facilities in new systems designs or a retrofit or conservation programme.     

Adapted stream region for packet marking based on DDoS attack detection in vehicular ad hoc networks

The Journal of Supercomputing - Vehicular ad hoc networks (VANETs) are a group of nodes that remain dynamically and randomly situated. VANETs are considered as one of the most prominent...     

Cloud resource allocation schemes: review,taxonomy, and opportunities

Cloud computing has emerged as a popular computing model to process data and execute computationally intensive applications in a pay-as-you-go manner. Due to the ever-increasing demand for cloud-based applications, it is becoming difficult to efficiently allocate resources according to user requests while satisfying the service-level agreement between service providers and consumers. Furthermore, cloud resource heterogeneity, the unpredictable nature of workload, and the diversified objectives of cloud actors further complicate resource allocation in the cloud computing environment. Consequently, both the industry and academia have commenced substantial research efforts to efficiently handle the aforementioned multifaceted challenges with cloud resource allocation. The lack of a comprehensive review covering the resource allocation aspects of optimization objectives, design approaches, optimization methods, target resources, and instance types has motivated a review of existing cloud resource allocation schemes. In this paper, current state-of-the-art cloud resource allocation schemes are extensively reviewed to highlight their strengths and weaknesses. Moreover, a thematic taxonomy is presented based on resource allocation optimization objectives to classify the existing literature. The cloud resource allocation schemes are analyzed based on the thematic taxonomy to highlight the commonalities and deviations among them. Finally, several opportunities are suggested for the design of optimal resource allocation schemes.     

Unicast routing protocols for urban vehicular networks: review,taxonomy, and open research issues

Over the past few years, numerous traffic safety applications have been developed using vehicular ad hoc networks（VANETs）. These applications represent public interest and require network-wide dissemination techniques. On the other hand, certain non-safety applications do not require network-wide dissemination techniques.Such applications can be characterized by their individual interest between two vehicles that are geographically apart. In the existing literature, several proposals of unicast protocols exist that can be used for these non-safety applications. Among the proposals, unicast protocols for city scenarios are considered to be most challenging.This implies that in city scenarios unicast protocols show minimal persistence towards highly dynamic vehicular characteristics, including mobility, road structure, and physical environment. Unlike other studies, this review is motivated by the diversity of vehicular characteristics and difficulty of unicast protocol adaption in city scenarios.The review starts with the categorization of unicast protocols for city scenarios according to their requirement for a predefined unicast path. Then, properties of typical city roads are discussed, which helps to explore limitations in efficient unicast communication. Through an exhaustive literature review, we propose a thematic taxonomy based on different aspects of unicast protocol operation. It is followed by a review of selected unicast protocols for city scenarios that reveal their fundamental characteristics. Several significant parameters from the taxonomy are used to qualitatively compare the reviewed protocols. Qualitative comparison also includes critical investigation of distinct approaches taken by researchers in experimental protocol evaluation. As an outcome of this review, we point out open research issues in unicast routing.     

A new technique for simultaneous water and energy minimisation in process plant

This paper presents a new technique for simultaneous minimisation of water and energy in process plants through a combination of numerical and graphical tools. The technique consists of three steps, namely, setting the minimum water and wastewater targets; design of minimum water utilisation network, and finally, heat recovery network design. This technique offers two key advantages over current state-of-the art techniques. Firstly, it is applicable to mass transfer based and non-mass transfer based water-using operations. Secondly, it introduces a new graphical visualisation tool through a plot of temperature versus stream flowrate, termed as heat surplus diagram to guide water and energy reduction simultaneously. The heat surplus diagram provide insights on the energy demand as well as on stream matching scenarios during design of a maximum water and energy recovery network. A case study on a paper mill plant demonstrates that significant reductions in water and energy consumption can be achieved using this approach.     

Development of Design Response Spectra Based on Various Attenuation Relationships at Specific Location

Peninsular Malaysia is located and lies in a low seismic region. Although Malaysia is not located in the active fault seismic area, it is closed to the Sumatran active seismic zones. Tall building are fIequently felt the tremor generated fTom Sumatran subduction and fault zones especially in the west cost of Peninsular Malaysia such as Johor Bahru, Kuala Lumpur and Penang. Existing design response spectra was developed based on attenuation relationship for each subduction and fault zone. In this study, the design response spectra were developed based on various attenuation relationships for selected location in Kuala Lumpur area, namely, Mutiara Damansara, Bandar Petaling Jaya and Bandar Puteri Puchong. The development of design response spectra based on various attenuation relationships is more reliable in selecting the appropriate attenuation relationship for the study area. Seven attenuations have been chosen and results show that Megawati et al. are the most appropriate attenuation relation for fault zone, where the predicted PGA （peak ground acceleration） is 0.0187 g which is the proposed PGA value for this study area. This study also found that most of soil in the study area can be categorized into SD （stiff soil） according to site classification in the NEHRP 2000 Provision/UBC 97. Bandar petaling Jaya was found to be highest AF （amplification factor） of 3.74 for stiff soil and Mutiara Damansara with AF of 2.67 for very dense soil or soft rock. The proposed design response spectra for each location were developed based on UBC 1997 （Uniform Building Code 1997）. The peak RSA （response spectrum acceleration） of 0.30 g for soil type SD for Bandar Petaling Jaya is the maximum level of acceleration on the soil surface with a period range of 0.10 to 0.52 seconds. All these values can be used for the seismic safety evaluation of existing structures and as a guideline in designing new structures to resist future earthquake, within the study area.     

电子管末级功率放大器的使用和维护

末级电子管功率放大器是电视发射机的主要部件,电视发射机维修费用的90%用于电子管放大器的维修,电视信号质量指标好坏与末级放大器的工作状态紧密相关.使用、维护好电子管放大器能大大降低维修成本、延长发射机寿命、提高画面质量,确保安全播出.正确使用和科学维护至关重要.     

Optimal heat exchanger network synthesis with operability and safety considerations

Research on the optimal design of heat exchanger networks (HENs) has primarily revolved around trading off technical design requirements for aspects of economy, such as capital cost of heat exchangers and utilities. As a result, considerations for safety, operability, and flexibility have received much less attention. This study presents a Pinch Analysis-based methodology that considers the inherent safety and operability aspects of an optimal HEN design. The procedure begins with data extraction, followed by utility targeting that gives due consideration to how each process stream impacts the inherent safety of the HEN. This is made possible via the use of a hot and cold Stream Temperature versus Enthalpy Plot (STEP) that prioritises the inherent safety index (ISI) on top of the heat capacity flow rate (CPs) during simultaneous targeting and design of the HEN. The Pinch temperatures and minimum utilities were determined using STEP. At the same time, the hot and cold stream pairs with higher ISIs and those with lower ISIs were matched together so that safety considerations could be emphasised and precautions taken with a particular heat exchanger. The disturbance propagation path through the HEN and the affected streams were also analysed. Network modification was performed using the downstream path concept in order to reduce disturbance propagation downstream of the HEN. The ?T _min violations and energy penalties from network changes were assessed. Flexibility and structural controllability of each network option were compared. The highest percentage of change in every stream of the network indicates that network is the most flexible, while the index of structural controllability closest to 1 demonstrates that the network is most controllable. Application of this method within an illustrative case study showed that network 3 was the most flexible as it yielded the highest percentage of change at 22 %. It was also the most controllable as it had a controllability index closest to 1.0, i.e. at 0.917.