The Productivity Slowdown, Measurement Issues, and the Explosion of Computer Power

macroeconomics, Productivity Slowdown, Measurement Issues, Computer Power

Design Principles for Closed Loop Supply Chains

In this paper we study design principles for closed loop supply chains. Closed loop supply chains aim at closing material flows thereby limiting emission and residual waste, but also providing customer service at low cost. We study 'traditional' and 'new' design principles known in the literature. It appears that setting up closed loop supply chains requires some additional design principles because of sustainability requirements. At the same time however, we see that traditional principles also apply. Subsequently we look at a business situation at Honeywell. Here, only a subset of the relevant design principles is applied. The apparent low status of reverse logistics may provide an explanation for this. To some extent, the same mistakes are made again as were 20 years ago in, for instance, inbound logistics. Thus, obvious improvements can be made by applying traditional principles. Also new principles, which require a life cycle driven approach, need to be applied. This can be supported by advanced management tools such as LCA and LCC.reverse logistics;case-study;closed loop supply chains

M.I.N.G., Mars Investment for a New Generation: Robotic construction of a permanently manned Mars base

A basic procedure for robotically constructing a manned Mars base is outlined. The research procedure was divided into three areas: environment, robotics, and habitat. The base as designed will consist of these components: two power plants, communication facilities, a habitat complex, and a hangar, a garage, recreation and manufacturing facilities. The power plants will be self-contained nuclear fission reactors placed approx. 1 km from the base for safety considerations. The base communication system will use a combination of orbiting satellites and surface relay stations. This system is necessary for robotic contact with Phobos and any future communication requirements. The habitat complex will consist of six self-contained modules: core, biosphere, science, living quarters, galley/storage, and a sick bay which will be brought from Phobos. The complex will be set into an excavated hole and covered with approximately 0.5 m of sandbags to provide radiation protection for the astronauts. The recreation, hangar, garage, and manufacturing facilities will each be transformed from the four one-way landers. The complete complex will be built by autonomous, artificially intelligent robots. Robots incorporated into the design are as follows: Large Modular Construction Robots with detachable arms capable of large scale construction activities; Small Maneuverable Robotic Servicers capable of performing delicate tasks normally requiring a suited astronaut; and a trailer vehicle with modular type attachments to complete specific tasks; and finally, Mobile Autonomous Rechargeable Transporters capable of transferring air and water from the manufacturing facility to the habitat complex

Periodic subgraph mining in dynamic networks

La tesi si prefigge di scoprire interazioni periodiche frequenti tra i membri di una popolazione il cui comportamento viene studiato in un certo arco di tempo. Le interazioni tra i membri della popolazione sono rappresentate da archi E tra vertici V di un grafo. Una rete dinamica consiste in una serie di T timestep per ciascuno dei quali esiste un grafo che rappresenta le interazioni attive in quel dato istante. Questa tesi presenta ListMiner, un algoritmo per il problema dell’estrazione di sottografi periodici. La complessità computazionale di tale algoritmo è O((V+E) T2 ln (T /σ)), dove σ è il minimo numero di ripetizioni periodiche necessarie per riportare il sottografo estratto in output. Questa complessità propone un miglioramento di un fattore T rispetto l’unico algoritmo noto in letteratura, PSEMiner. Nella tesi sono inoltre presenti un’analisi dei risultati ottenuti e una presentazione di una variante del problem

Towards a developmental state? Provincial economic policy in South Africa

This paper explores the meaning of the developmental state for spatial economic policy in South Africa. Two main questions are addressed: do provincial governments have a role to play in promoting economic prosperity, and to what extent do current provincial policies possess the attributes of a developmental state? These attributes are defined as the ability to plan longer term, to focus key partners on a common agenda, and to mobilise state resources to build productive capabilities. The paper argues that the developmental state must harness the power of government at every level to ensure that each part of the country develops to its potential. However, current provincial capacity is uneven, and weakest where support is needed most. Many provinces seem to have partial strategies and lack the wherewithal for sustained implementation. Coordination across government appears to be poor. The paper concludes by suggesting ways provincial policies could be strengthened

Definitions and Measures of ICT Impact on Growth: What is Really at Stake?

Many innovations have been introduced in national accounts in order to better gauge the information and communication technologies (ICT) diffusion impact: new ICT definitions; recognition of business and government software expenditures as fixed investment; hedonic price index. Nevertheless, there still does not exist any clear consensus about the magnitude of the ICT impact on growth. Our aim is to propose some explanations of this relative failure and also show that the debate should not be exclusively centered on quantitative methods. To this end, we take a close look at the two main questions concerning the debate surrounding the measure of the ICT impact: 1) Are there any substantial total factor productivity (TFP) gains generated by ICT diffusion or is it only a classic story of capital deepening increase ? 2) If there are indeed TFP gains, are they limited to ICT producers, as Robert J.Gordon claims, or is there any diffusion to ICT users ? The answer to the first question is really important only if it determines the length and the extent of an eventual growth cycle impulsed by ICT. The possibility that productivity gains mainly due to capital deepening generate strong and durable growth has been theoritically demonstrated by Greenwood and Jovanovic (1998), thanks to a vintage capital model. We precise the conditions under which this result can be obtained and discuss their empirical relevance. According to this approach, the true debate concerns the durability of the present technological shock, instead of its capacity to generate an autonomous technical progress. The answer to the second question is crucial because it could guide industrial policy choices. If TFP gains are limited to ICT producers, should a country always be an ICT producer, or will it anyway grow at a strong pace thanks to the fall of ICT prices ? The relevance of this economic debate is unfortunately poised by the shortcomings of available statistical tools. On one hand, the distinction between ICT users and producers is purely discretionary. On the other hand, TFP measure is completely distorted by the method used to evaluate the value of capital (cost-based prices against adjusted-quality prices). That is why we argue that the international diffusion of growth gains due to ICT essentially depends on the capacity of ICT producers' countries to stay in a rent keeping situation. The text is divided into two parts. The first one first makes a quick assessment of the adaptation of american national accounts to the " new economy ", and then underlines the limits of these changes. The second one shows that the economic debate on the importance of TFP gains acceleration and where they occur, although more complex because of these limits, can quite ignore them thanks to the implications of some endogeneous growth and international trade models.ICT; multifactor productivity; national accounts; hedonic prices

Context-awareness for mobile sensing: a survey and future directions

The evolution of smartphones together with increasing computational power have empowered developers to create innovative context-aware applications for recognizing user related social and cognitive activities in any situation and at any location. The existence and awareness of the context provides the capability of being conscious of physical environments or situations around mobile device users. This allows network services to respond proactively and intelligently based on such awareness. The key idea behind context-aware applications is to encourage users to collect, analyze and share local sensory knowledge in the purpose for a large scale community use by creating a smart network. The desired network is capable of making autonomous logical decisions to actuate environmental objects, and also assist individuals. However, many open challenges remain, which are mostly arisen due to the middleware services provided in mobile devices have limited resources in terms of power, memory and bandwidth. Thus, it becomes critically important to study how the drawbacks can be elaborated and resolved, and at the same time better understand the opportunities for the research community to contribute to the context-awareness. To this end, this paper surveys the literature over the period of 1991-2014 from the emerging concepts to applications of context-awareness in mobile platforms by providing up-to-date research and future research directions. Moreover, it points out the challenges faced in this regard and enlighten them by proposing possible solutions