铁道部计算机网络安全技术方案、效果及成功案例

针对铁道部网络安全的现状,提出解决问题的技术方案,并对其效果进行说明.铁道部计算机网络安全技术方案的主要内容包括:铁路系统信任体系的建设,对互联网边界、局域计算环境、网络基础设施进行的保护,以及复杂网络系统的集中式安全管理.并通过铁道部网络安全工程的成功案例,展现在纵深防御体系基础上实现的网络访问控制功能.最后,对本方案的应用前景进行了展望.     

A GIS‐based traffic analysis zone design: technique

The main purpose of this paper is to develop an efficient method to design traffic analysis zones (TAZs), which is necessary for implementing a planning process with Geographic Information System (GIS) for Transportation (GIS‐T), using statistical spatial data analyses and GIS technology. The major roles of GIS in this method are: (1) to produce basic spatial units (BSUs) with topological data structure; (2) to integrate various procedures during the TAZ generation including computer program routines; and (3) to visualize the output of each TAZ generation. One of the most significant reasons for obtaining well‐defined TAZs is the fact that they are defined at the outset of transportation demand modeling, used from trip generation to trip assignment, and will ultimately affect transportation policy decisions.

Toward obtaining well‐defined TAZs, this paper concentrates on two important constraints: homogeneity and contiguity. Iterative partitioning technique is adopted to promote the optimum homogeneity of generated TAZs, while a contiguity checking algorithm is developed to ensure contiguous TAZs are generated by the iterative partitioning technique.     

Monitoring Loggerhead Sea Turtle (Caretta caretta) Nests in Turkey Using GIS

Both the loggerhead sea turtle (Caretta caretta) and the green turtle (Chelonia mydas) live, feed, and nest in the Mediterranean, mostly on the beaches of Turkey and Greece. The greatest threat to the survival of Caretta caretta has been found to be on the sandy beaches where their lives begin. In this study, the digital terrain model (DTM) of the Iztuzu Beach in Turkey where the Caretta caretta sea turtles lay their eggs was prepared using a global positioning system (GPS) and a geographic information system (GIS). A flexible coastal geographic information system was prepared integrating the DTM with digitally processed satellite images and ground truth of the nesting area and its surroundings. Researchers, decision makers, other end users, or sea turtle experts can find and query any environmental information having a possible impact on the nesting area using a computer-based GIS database. A multidate monitoring of the nesting area allows users to extract and compare much information about the location and condition of the nests and will help researchers develop better strategies for protecting sea turtles.     

An analysis of internal transit systems requirements for central cities

The deficient performance of existing downtown transit distribution systems may significantly affect the overall performance of the urban transportation system in many metropolitan areas. This paper has two principal objectives. First, it describes an approach entitled Performance Requirements Analysis for developing a set of requirements or standards that a downtown transit system should satisfy and structuring these requirements so as to generate a small set of alternative generic systems for detailed evaluation. Second, it provides a preliminary assessment of performance requirements for distribution systems in 19 of the largest cities in the United States.     

香港地区实施ISM工作现状及思考

文中介绍了香港地区实施ISM规则(国际安全管理规则)机构、立法及实施的相关情况,着重分析了《香港商船(安全)条例》涉及ISM规则的有关规定和执行,总结了香港地区航运公司管理和实施ISM规则的特点,提出了国内ISM/NSM规则的实施及相关工作的建议。     

Real-world gaseous and particle emissions of a Bi-fuel gasoline/CNG Euro 6 passenger car

The objective of the present study is the assessment of the environmental impact of a bivalent (bi-fuel) vehicle, running either on gasoline or compressed natural gas (CNG). To that aim, a Euro 6 passenger car was tested under various real-world driving conditions. In order to cover the full range of conventional powertrains currently in the market, the tests were also repeated on a Euro 6 diesel passenger car. Both cars were driven in two routes, the first complying with the regulation limits and the second going beyond them. Carbon monoxide (CO), nitrogen oxides (NO_x) and particle number (PN) emissions were recorded using a Portable Emissions Measurement System (PEMS). Apart from the aggregated emission levels, in g/km, the exact emission location along the route was also assessed. Natural gas proved beneficial for CO and PN emissions, the level of which always remained below the respective legislation limits. On the other hand, under the dynamic driving conditions with gasoline, the relevant limits were exceeded. Cold start, occurring at the beginning of the urban part, and motorway driving were identified as major contributors to total emissions, especially in gasoline mode. However, the application of natural gas was associated with a penalty in NO_x emissions, which were significantly increased as compared to gasoline. Local peaks within the urban part were identified in CNG mode. In any case, the diesel vehicle was by far the highest NO_x emitter.     

海洋核动力平台自然冷却供冷系统节能性分析

针对海洋核动力平台示范工程运行厂址及其堆舱区供冷需求特点,为提高运行经济性,设计了利用自然冷源——海水的供冷系统,通过建立系统能耗模型,分析了不同海水温度下系统运行工况及相应的能耗和能效比。根据运行厂址实测海水温度,计算了系统优化前后全年运行能耗,并分析了节能效果,系统优化后节能15.7%。     

Characterizing the fragmentation level of Italian’s National Parks due to transportation infrastructures

In the last decades, due to the population increase and the relative need of new land to cultivate, expand urban centers and develop transportation networks, most of the Italian natural protected areas are subject to different typologies of human pressures that generally cause habitat fragmentation. This process represents a major concern for biodiversity conservation and a key driver of species loss.The main purpose of this paper was to investigate levels of natural habitat fragmentation due to roads and railways networks in the Italian National Parks (INP_S) through the use of an Infrastructural Fragmentation Index (IFI).All the operations (geospatial analysis, image classification, and fragmentation analysis) were performed using a Geographic Information System (GIS) software for elaborating a national database. The obtained results include an IFI value for each natural territorial unit inside any INP. Moreover, in order to highlight which are the INP_S characterized by higher infrastructural fragmentations, an IFI weighted mean was calculated for each INP. These results represent important indicators for the prioritization of biodiversity conservation interventions and the planning of a INP_S sustainable management.     

System dynamics of urban traffic based on its parking-related-states

The urban parking and the urban traffic systems are essential components of the overall urban transportation structure. The short-term interactions between these two systems can be highly significant and influential to their individual performance. The urban parking system, for example, can affect the searching-for-parking traffic, influencing not only overall travel speeds in the network (traffic performance), but also total driven distance (environmental conditions). In turn, the traffic performance can also affect the time drivers spend searching for parking, and ultimately, parking usage. In this study, we propose a methodology to model macroscopically such interactions and evaluate their effects on urban congestion.The model is built on a matrix describing how, over time, vehicles in an urban area transition from one parking-related state to another. With this model it is possible to estimate, based on the traffic and parking demand as well as the parking supply, the amount of vehicles searching for parking, the amount of vehicles driving on the network but not searching for parking, and the amount of vehicles parked at any given time. More importantly, it is also possible to estimate the total (or average) time spent and distance driven within each of these states. Based on that, the model can be used to design and evaluate different parking policies, to improve (or optimize) the performance of both systems.A simple numerical example is provided to show possible applications of this type. Parking policies such as increasing parking supply or shortening the maximum parking duration allowed (i.e., time controls) are tested, and their effects on traffic are estimated. The preliminary results show that time control policies can alleviate the parking-caused traffic issues without the need for providing additional parking facilities. Results also show that parking policies that intend to reduce traffic delay may, at the same time, increase the driven distance and cause negative externalities. Hence, caution must be exercised and multiple traffic metrics should be evaluated before selecting these policies.Overall, this paper shows how the system dynamics of urban traffic, based on its parking-related-states, can be used to efficiently evaluate the urban traffic and parking systems macroscopically. The proposed model can be used to estimate both, how parking availability can affect traffic performance (e.g., average time searching for parking, number of cars searching for parking); and how different traffic conditions (e.g., travel speed, density in the system) can affect drivers ability to find parking. Moreover, the proposed model can be used to study multiple strategies or scenarios for traffic operations and control, transportation planning, land use planning, or parking management and operations.     

加强铁路法制建设促进铁路跨越式发展

加强铁路法制建设,是铁路跨越式发展战略的重要组成部分。近年来,铁道部围绕铁路跨越式发展对法制保障的需要,加大了法制建设力度,取得了一系列成果,立法取得重大突破,依法行政得到有序推进,企业的法治化管理得到加强。但也存在一些问题,铁路法规体系还不完整,依法行政理念还不深入,企业法律风险意识还不强。需要重点抓好:健全铁路法规体系、全面推进依法行政、依法推进铁路改革、依法规范铁路运输经营管理、依法保障大规模铁路建设的实施、加大法制宣传教育力度、加强法律队伍建设等工作,确保铁路跨越式发展战略的顺利实施。