Probing A Traffic Congestion Controversy: A Comment

Ohta (2001) claims to have resolved a die-hard controversy on traffic congestion modeling by defining an inverse aggregate demand function that has traffic density as its argument—in Ohta's terminology the 'primitive term.'Using this demand function, Ohta shows that 'hypercongestion' may very well be an optimal stationary state. This contribution argues that at least if what road users demand is completed trips, and if time spent on the road while traveling implies a cost, then Ohta's approach is fundamentally flawed. Also the conclusion that hypercongestion can be optimal is no longer valid.     

The Location Invariance Theorem in Weberian Space Under Uncertainty

This paper examines the validity of the location invariance theorem in Weberian space under various types of uncertainty. The main results are: Given that the firm's location is constrained to remain at a specified distance from the output market, the optimal location is invariant to any change in product demand if and only if the production function is homothetic for a firm facing demand price uncertainty, or if the production function is homothetic and both inputs are risk-neutral for a firm facing technological uncertainty. Alternatively, given that the distance from the firm's location to the output market is a variable, location invariance occurs for a firm facing demand price uncertainty if the production function is linear homogeneous. In the presence of input price uncertainty the optimal location always varies with a change in product demand. The results can include those previously obtained for linear stochastic location models as special cases and some are new contributions to the literature.     

部类编排法应成为方志编纂学的一个基本原则——关于综合性方志部类设置的实践与思考

修志史上无所谓部类编排法,但类似部类设置的现象早已有之。在中华人民共和国成立后的两轮综合性新方志编修中,以部类谋篇布局是广泛采取并普遍认可的重要方法,这既是社会实践进程不断深化和现代科学迅速发展的必然要求和反映,也符合加强志书整体性和志书内容有机联系的发展趋势,因此部类编排法应成为方志编纂学的一个基本原则。确定部类范畴要遵循科学性、现实性、可行性三大依据,划分部类内容应坚持致用性、时代性、权威性、严谨性、包容性、开放性六大原则,实践中可借鉴六大部类、八大部类、十大部类三种参考模型,灵活运用基本原则,根据不同地情特点作出各自不同的取舍。     

Optimal Facility Location in a One-Dimensional Spatial Market

This paper analyzes properties of the optimal spatial arrangement of what may be interpreted as a class of public facilities. Optimality is defined as cost minimization. Three different optimality criteria are considered, and for each, the necessary and, sufficient conditions, market area size, and production levels, are derived. The relationship between optimal production levels and number of facilities needed is also considered. Next the results of implementing various pricing strategies are analyzed with emphasis given to marginal and uniform pricing. It is shown that, given certain conditions, all facilities incur operating deficits, given marginal pricing. Estimates on the level of the deficits are derived in terms of location rents. Finally, in the appendix, several important results from other studies are derived as special cases of the basic model.     

Optimality in Two Spatially Separated Periodic Markets

A recursive analysis is made of a two market, trader-coupled, periodic marketing system with collapsing and recovering, nonlinear, demand and supply schedules. It yields time series in all prices and commodity flows. Conditions are established for maximum weekly social surplus, for the existence, uniqueness, and asymptotic stability of steady states, and for an optimal number of days for the marketing week.     

On the Finite Optimality Set of the Vector Assignment p‐Median Problem

The vector assignment p‐median problem (VAPMP) is one of the first discrete location problems to account for the service of a demand by multiple facilities, and has been used to model a variety of location problems in addressing issues such as system vulnerability and reliability. Specifically, it involves the location of a fixed number of facilities when the assumption is that each demand point is served a certain fraction of the time by its closest facility, a certain fraction of the time by its second closest facility, and so on. The assignment vector represents the fraction of the time a facility of a given closeness order serves a specific demand point. Weaver and Church showed that when the fractions of assignment to closer facilities are greater than more distant facilities, an optimal all‐node solution always exists. However, the general form of the VAPMP does not have this property. Hooker and Garfinkel provided a counterexample of this property for the nonmonotonic VAPMP. However, they do not conjecture as to what a finite set may be in general. The question of whether there exists a finite set of locations that contains an optimal solution has remained open to conjecture. In this article, we prove that a finite optimality set for the VAPMP consisting of “equidistant points” does exist. We also show a stronger result when the underlying network is a tree graph.     

Optimizing the Spatial Structure of the Agricultural Production Function

Important characteristics of spatial agricultural production functions are derived by introducing a non‐negative curvilinear spatial demand function for production input intensities. Given the usual neoclassical rationale assumptions of spatial demand for capital and labor inputs under competitive environment of farming in developing agricultural economies, the optimal production levels are determined by optimizing spatial demand for production inputs. Decreasing price‐to‐transport costs ratio (that is, decrease in the prices of capital goods or increase in freight rates) and increasing wage‐to‐travel costs ratio (that is, increase in labor wages or decrease in the travel rate) expand the limits of the (spatial) optimal boundary of the demand for agricultural capital goods and labor input respectively. These effects occur on account of the operation of (positive) spatial price gradient and (negative) wage‐gradient in the market region. It may be noted that elasticities of demand for production factors are spatially variant and have significant effects on the alterations in the structure of agricultural production. However, the spatial optimal solution of production has a complicated relationship with them. The price elasticity has negative and wage elasticity has positive spatial gradients in the market region. Farmers located in the periphery of the market region are not much affected by the proportionate changes occurring in the prices of agricultural capital goods but are more sensitive to the proportional changes in labor wages. Because of a decreasing trend in capital input demand and increase in labor input with distance from the market, capital‐product diminishes with a decreasing rate and labor‐product increases with an increasing rate in the spatial structure of agricultural production. As a result, capital‐labor ratio falls toward zero, which raises profit rate per unit of capital investment especially in the outer part of the market region. The equilibria of optimal production with price elasticity as well as of capital intensity with labor employment (that is, capital‐labor ratio as unity) determine spatial limits of the optimal production zone which is shifted outward subject to the provision of cheap transportation, stabilizing market prices and/or increasing wage rate at the market center. It will help in extending outwardly the optimal spatial limits of capital investment and will mobilize capital resources of farmers in the periphery for efficient and competitive capital‐dominated farming.     

时空转换中的行宫图像——对几件《盘山图》的研究

本文以清代乾隆帝《盘山图》轴为主要研究对象,分析画面空间处理方式,并着重解读画上的题诗,从题诗的时间顺序、位置布局、主题内容、诗体形式、诗后钤印等方面,结合历史背景,剖析乾隆帝在漫长岁月中的心理变化,指出《盘山图》轴通过大量有纪年的题诗,将时间的流逝留驻于空间的布置之中,使画与历法联系起来,从而使这幅普通的山水画具有了更为深层的意识形态价值。此外,作者也研究了董邦达创作的《田盘胜概图》册和《盘山十六景图》卷,与《盘山图》轴和《盘山志》版画插图等材料进行对比分析,发现画法精细的《田盘胜概图》册在写实的表象之下具有高度风格化的倾向;《盘山十六景图》卷同样对空间作了风格化的处理,通过压缩、位移等技术手法,加上观看必需的时间过程,使画面空间与时间维度联系起来,这是长卷构图固有的特性,与《盘山图》立轴式的时空交融方式形成了对比。乾隆帝不选择适于书写题跋的《盘山十六景图》卷拖尾题诗,而选择在《盘山图》轴上局促的空白处题诗,更证明了他对《盘山图》轴有特殊的意匠经营。     

城市职能演变的回顾与展望

全球化是当前世界发展的主流,全球化对城市的发展已经产生了深远的影响,一方面生产要素在城市之间的流动加强。另一方面城市主导权力扩大。加剧了城市之间的竞争。由此带来城市产业结构和产业布局的变化,促进了城市化、郊区化、绅士化等的发展。在此背景之下,全球城市在人类社会发展中的职能不断演变。其基本趋势是由生产性职能转向服务性职能。并且这种演变会伴随着全球信息化的发展逐步由多元服务向单一的人居服务发展。本在对全球城市职能演变简单回顾的基础上。根据全球化发展的趋势。探讨了全球化对城市职能演变的影响,并预测未来城市职能的变化趋势。     

社会转型中的制度供给与需求--民初国会失败原因再探讨

民初建立的包括国会在内的一整套民主共和制度是一种供给主导型的制度变迁,这种变迁模式的成败取决于提供制度变迁的权力主体是否具有权威和理想。这一制度第一供给主体是南京临时政府,他们有理想但缺少权威,第二供给主体是北京政府,他们有权威但无理想。国会作为民主政治生活中限制个人独裁、维护公民权利的根本措施,就无法成功地在中国运行。制度需求的缺失也是造成国会失败的原因之一,但不是主要原因。     

Planning Time: An Emergent European Practice

In the 1960s, a reduction in the time spent at work promised an increase in leisure time. Architects and planners thought that the effects of this could lead to a new form of city. Nowadays, new changes in production, technology and gender relationships de-synchronize the time regime and have fundamentally changed life in cities. Tourism and globalization exchange across the world different cultures of time. In France, the UK, and other European countries time policy is dealing with the problems arising from these changes. This article presents a short overview of time planning in Italy in two main domains: time for care, and city time. It focuses on issues such as the social demand for new shops's and services' opening hours, or how the life cycles of individuals and populations are accommodated in urban spaces. Other problems, usually not thought of in terms of time concerns, such as rehabilitation of blighted areas, historic preservation and traffic flow control, may also be treated through a time approach. Two models of planning process are presented at the end of the paper.     

Asia's century and the problem of Japan's centrality

Japan has long been regarded as a central component of America's grand strategy in Asia. Scholars and practitioners assume this situation will persist in the face of China's rise and, indeed, that a more ‘normal’ Japan can and should take on an increasingly central role in US‐led strategies to manage this power transition. This article challenges those assumptions by arguing that they are, paradoxically, being made at a time when Japan's economic and strategic weight in Asian security is gradually diminishing. The article documents Japan's economic and demographic challenges and their strategic ramifications. It considers what role Japan might play in an evolving security order where China and the US emerge as Asia's two dominant powers by a significant margin. Whether the US–China relationship is ultimately one of strategic competition or accommodation, it is argued that Japan's continued centrality in America's Asian grand strategy threatens to become increasingly problematic. It is posited that the best hope for circumventing this problem and its potentially destabilizing consequences lies in the nurturing of a nascent ‘shadow condominium’ comprising the US and China, with Japan as a ‘marginal weight’ on the US side of that arrangement.     

Public–private partnerships in national cyber‐security strategies

Despite its centrality in the national cyber security strategies of the US and the UK, the public–private partnership is a nebulous arrangement, which is especially problematic in the context of critical infrastructure protection. Privately owned and operated critical infrastructure that is regarded as a potential national security vulnerability raises questions about the allocation of responsibility and accountability in terms of cyber security. As with many aspects of cyber security, this issue is often discussed with little reference to previous scholarship that could provide conceptual scaffolding. This article draws on the extensive literature on public–private partnerships in order to assess the tensions and challenges of this arrangement in national cyber‐security strategies. It finds that there is a serious disjuncture in expectations from both ‘partners’. The government regards privately owned and operated critical infrastructure as a key element of national security but is reluctant to claim a mandate to oversee network security. At the same time, the private sector is not inclined to accept responsibility or liability for national cyber security. This challenge for governments to manage national cyber security raises questions about how well equipped these states are to promote their own security in the information age. Acknowledging the flaws in the ‘partnership’ is an essential step towards addressing them.     

THE OPTIMAL LOCATIONS OF BRANCH FACILITIES AND MAIN FACILITIES WITH CONSUMER SEARCH*

ABSTRACT. This paper examines the socially optimal locations of branch facilities (or small stores) and main facilities (or large stores) on a finite linear market that is uniformly populated from position 0 to position 1. Each consumer has a probability w of finding the desired service (or product) at a branch facility, and a probability 1 of finding the desired service (or product) at a main facility. Two types of consumer search are considered: phone search and visit search. Different assumptions are made about the numbers of branch facilities and main facilities (each involving one or two facilities of each type). Under visit search, the socially optimal locations of branch facilities tend to be closer to main facilities than under phone search, and this tendency is more pronounced for smaller values of w.     

Importing and exporting spatial needs: A Dutch approach1

The increasing demand for space determines much of the approach to spatial planning in countries with a high population density like the Netherlands. In the next three decades more land will be needed for housing, work, traffic, leisure, nature and water. There is only one sector that will yield land: agriculture. The Dutch Minister of Spatial Planning has presented six intervention strategies to cope with the increasing demand for space: (1) priority setting; (2) export spatial needs; (3) reduce the need for space in accordance with policy; (4) intensify land use; (5) combine spatial needs; (6) transform spatial structures and buildings. Spatial planning in the Netherlands is becoming more and more geared to strategies 4, 5 and 6, which take the need for land as given. This paper seeks to explain that the first three strategies, and strategy 2 in particular, are also crucial for a country like the Netherlands, even though the policies associated with them would not generally be labelled spatial. For the spatial planner, however, the export of spatial needs is relevant as this determines the outcome of spatial planning to a large extent. This shall be illustrated by reporting on international residential migration, the use of leisure homes and second homes, international business migration and the restructuring of the agricultural sector. The Netherlands is not only exporting spatial needs, but also in the same time even imports needs at a larger scale, which puts spatial planning on a larger pressure. In the past the lack of space was solved by relinquishing land that was originally earmarked for water or nature. But the need for space for water and nature has increased recently and will continue to do so in the coming decades. This makes intervention strategy 2 even more relevant for the future. Spatial planners need to widen their horizons and include the import and export of spatial needs in their analyses.     

Probing A Traffic Congestion Controversy: Density and Flow Scrutinized

Probing a die-hard traffic congestion controversy, this paper scrutinizes two key variables, density and flow, under equilibrium versus optimal states. Optimization requires equilibrium flow to decrease under mild congestion, but increase under hyper-congestion. However, both increasing flow needed under hypercongestion and decreasing flow needed under mild congestion should be accompanied by decreasing density. Thus, inflow of vehicles should always be discouraged to either increase or decrease flow of vehicles for economic efficiency. Moreover, even when optimal policy requires equilibrium flow to increase, the optimal flow itself must decrease eventually as demand increases beyond a critical level.     

Ancient Maya wood selection and forest exploitation: a view from the Paynes Creek salt works,Belize

Ancient building construction wood preserved in a peat bog below the seafloor in a shallow mangrove lagoon in Paynes Creek National Park, Belize, provides an exceptional record of Classic Maya wood use. Identifications of construction wood at Early Classic Chan B'i, and Late Classic Atz'aam Na, are reported and discussed to assess forest exploitation and species selection over time. Black mangrove (Avicennia germinans) dominates the Early Classic assemblage. The Late Classic assemblage is characterized by greater variability and an absence of mangrove species. When considered in the environmental context, identified species conform to principles of optimal foraging. The change in the wood assemblage over time suggests overexploitation of forest resources, resulting in deforestation of the local landscape and subsequent adaptation of foraging behavior. Deforestation is linked to the wider social context in which growing inland populations created demand for salt, putting greater pressure on the forest resources exploited by the Paynes Creek salt works for fuel and timber.     

China's oil diplomacy in Africa

Within the next five years, Chinese trade with Africa is predicted to reach $100 billion per year. Much of this springs from China's growing expansion into Africa's oil markets. It is argued that Chinese oil diplomacy in Africa has two main goals: in the short-term to secure oil supplies to help feed growing domestic demand back in China; and in the long-term, to position China as a global player in the international oil market. Yet at the same time, this oil safari is being accompanied by an explicit stance that emphasizes state sovereignty and 'non-interference' in domestic affairs and is wholly disinterested in transparency or human rights. Consequently, Beijing has increasingly been accused of turning a blind eye to autocracy and corruption. China is also threatening to undercut efforts by the African Union and its western partners to make government and business more accountable. While China is providing investment where little was previously forthcoming, concerns about Beijing's engagement with Africa's oil industries need to be resolved, not least by African leaders themselves.     

基于网络大数据的城市内部便利性供需空间特征研究——以南京市中心城区为例

基于便利性的城镇发展战略对于新型城镇化转型具有重要意义。着眼于城镇居民生活质量的提升,围绕供需维度构建便利性测度体系,以多源网络大数据为支撑,分析南京市中心城区便利性的供需空间特征。结果表明,中心城区便利性供需关系多样,空间分布大体类似,倾向于多类聚合分布,并呈现较为明显的圈层集聚特征;主城便利性多供小于求,副城则以低供需平衡及供小于求为主,各公共活动中心便利性发育水平不一;中心城区整体便利性供需水平不高,其空间分布在数量及连续性方面均呈现低供需平衡、低供-中需以及中供-低需依次降低的模式。     

An Improved Displacement-Based Adaptive Pushover Procedure for the Analysis of Frame Buildings

The main purpose of this article is to develop an alternative adaptive pushover method in which multiple inelastic response spectra proportional to the instantaneous ductility ratio of the structure are employed to reflect the actual energy dissipation characteristic of the structure at a given deformation level. Based on the proposed methodology, two load patterns are independently applied to the structure and the envelope of the demand values is computed. The obtained results demonstrate that the proposed method provides improved predictions of the peak interstory and total drift profiles of the structure.