Location Privacy in Device-Dependent Location-Based Services: Challenges and Solution

With the evolution of location-based services (LBS), a new type of LBS has already gain a lot of attention and implementation, we name this kind of LBS as the Device-Dependent LBS (DLBS). In DLBS, the service provider (SP) will not only send the information according to the user’s location, more significant, he also provides a service device which will be carried by the user. DLBS has been successfully practised in some of the large cities around the world, for example, the shared bicycle in Beijing and London. In this paper, we, for the first time, blow the whistle of the new location privacy challenges caused by DLBS, since the service device is enabled to perform the localization without the permission of the user. To conquer these threats, we design a service architecture along with a credit system between DLBS provider and the user. The credit system tie together the DLBS device usability with the curious behaviour upon user’s location privacy, DLBS provider has to sacrifice their revenue in order to gain extra location information of their device. We make the simulation of our proposed scheme and the result convince its effectiveness.     

A review of hydrogen station location models

Hydrogen is emerging as a zero-carbon energy source for the sustainable future. Hydrogen station plays the role of supplying hydrogen to fuel cell vehicles. However, the small number of hydrogen stations has become the biggest obstacle to the promotion of hydrogen energy. As an important infrastructure for the development of hydrogen energy industry, the hydrogen station will not be able to support the promotion and application of hydrogen fuel cell vehicles if it cannot form a large scale. In addition, the layout of the hydrogen station network should be reasonable to avoid waste of resources. The study of hydrogen station location models has significant economic, social and military implications. Considering these circumstances, this review investigates the existing research efforts and conducted a comprehensive overview of these works on hydrogen station location models. In this review, we divide the hydrogen station location models into several categories according to the spatial dimension of the facility, the structure of the planning area, and the number of objectives. We present detailed explanations, formulations and different constraints for these models. Finally, we conclude the strengths and weaknesses of these models and provide available solutions. To our best knowledge, this review might help researchers get a comprehensive understanding of related researches in the hydrogen station location.     

p-Median and p-dispersion problems: A bi-criteria analysis

Given a collection of n locations and a symmetric measure of distance (difference) between each pair of locations, we seek to identify (select) a subset of p locations so as to achieve two distinct objectives. The first objective is to use the selected locations as centers (medians) of p groups that would partition the entire collection and minimize the total distance between the locations and their respective group medians. The second objective is to maximize the minimum distance (diversity) among the selected locations themselves. We study this problem as a multi-objective optimization problem and propose an iterative algorithm to obtain its non-dominated frontier. At each iteration we construct and solve a 0–1 integer programming problem. Through a computational experiment we show that this algorithm is computationally effective for small to medium size instances of the problem. We also propose a Lagrangian heuristic algorithm for solving larger instances of this problem.     

增强现实中基于位置安全性的LBS位置隐私保护方法

为了解决基于位置的服务(LBS)和增强现实(AR)技术快速发展带来的用户位置隐私泄露的隐患,分析了现有的位置隐私保护方法的优缺点,提出基于位置安全性的位置隐私保护方法。将区域安全度和伪装区域引入该方法中,将提示某区域是否需要保护这一度量标准定义为区域安全度,非安全区域(即需要给予保护的区域)的区域安全度设置为1,安全区域(即不需要保护的区域)设置为0,通过扩大区域安全度和识别等级来计算位置安全度。实验结果表明,该方法与未引入位置安全性的方法相比降低了平均定位误差,提高了平均安全性,从而有效地保护了用户的位置隐私,提高了LBS的服务质量。     

区位对城市边缘区村屯发展模式影响的研究

城市经济的发展带动城市边缘区的建设与开发。文章通过对区位要素与空间区位特征的研究与分析,得出区位对每个区域的发展模式存有影响。各村屯要根据自己所处的地理位置特征,合理定位,制定相适应的、可行的、动态的发展模式。     

A total environmental risk assessment model for international hub airports

This paper presents a multi-criteria decision analysis for environmental risk assessment (ERA) with regard to avoiding and eliminating damages and loss under natural disasters in international airport projects. It starts from an assumption that the strategy of eliminating damages and losses under natural disasters is related to the location selection problem, and it is necessary to use the multi-criteria decision analysis for calculated decision-making support. The paper uses the analytic network process (ANP) to demonstrate one of its utility modes in decision-making support to location selection problems, which aims at an evaluation of different projects from different locations. A set of generic criteria for risk assessment at international projects was put forward to support ANP modelling, and it was due to the consideration of social, technical, economic, environmental and political (STEEP) criteria related to the built, social and natural (BSN) trinity environment of international airport projects. At the end, an experimental case study on three international hub airports in China is given to test the ANP model called ERA.Airport, and it is concluded that ANP can be effectively used for risk assessment in the specific utility mode. The ERA.Airport is a generic multi-criteria decision-making model and can be used across the world for accurate environmental risk assessment for international airports.     

福州市GPS综合服务系统设计与研究

建立“区域GPS综合服务系统”代替离散、静态的区域定位基准,已成为进一步开发和应用GPS技术的新趋势。本文根据福州市实际情况,论述了福州市GPS综合服务系统的组成和功能,提出了福州市GPS综合服务网建设方案,同时讨论了系统建设过程中应重点解决的问题。     

南城民居的传统文化特色

民居设计反映了一定社会文化形态的影响。南城是我国东部沿海依山而建的古老城镇，古称凤凰城，历史文化源远流长，人们长期以来的商业活动，生活习俗，宗教信仰等孕育了自身独特的传统文化特色。古镇民居建筑的选址、布局、装饰特点的形成和发展深受传统文化的影响，古朴素雅，自成风格，在海州湾一带沿海地区颇具代表性。     

A pricing-based location model for deploying a hydrogen fueling station network

We propose an innovative two-step Pricing-Based Location strategy for the rollout of new hydrogen fueling stations. A first model maximizes the profit of a new station with a price p¹ which corresponds to a design capacity supplying a given market share (n¹ customers). According to these findings and with the objective of deploying an extensive network, a second model searches for a suitable location as remote as possible from existing competitors, but as close as possible to just n¹ demand locations. This problem is solved by an agent-based model integrating the Particle Swarm Optimization metaheuristic and a Geographic Information System representing the geospatial distribution of customer demand. We apply this model to the city of Paris by locating additional stations across the city one by one to supply a growing captive fleet of taxis and other transport operators in the future.     

A location–inventory supply chain problem: Reformulation and piecewise linearization

In this paper, we study a two-echelon inventory management problem with multiple warehouses and retailers. The problem is a natural extension to the well-known one-warehouse multi-retailer inventory problem. The problem is formulated as a mixed integer non-linear program such that its continuous relaxation is non-convex. We propose an equivalent formulation with fewer non-linear terms in the objective function so that the continuous relaxation of the new model is a convex optimization problem. We use piecewise linearization to transform the resulting MINLP to a mixed integer program and we solve it using CPLEX. Through numerical experiments, we compare the solutions obtained by solving the new formulation using CPLEX with two previously published Lagrangian relaxation based heuristics to solve the original mixed integer non-linear program. We demonstrate that the new approach is capable of providing almost the same solutions without the need of using specialized algorithms. This important contribution further implies that additional variants of the problem, such as multiple products, capacitated warehouses and routing, can be added to result in a problem that will again be solvable by commercial optimization software, while the respective Lagrangian heuristics will fail to solve such variants or extended problems.