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This paper analyzed the characteristic of the tourism destination ecosystem from perspective of entropy in Dunhuang City. Given these circumstances, an evaluation index system that considers the potential of sustainable development was formed based on dissipative structure and entropy change for the tourism destination ecosystem. The sustainable development potential evaluation model for tourism destination ecosystem was built up based on information entropy. Then, we analyzed each indicator impact for the sustainable development potential and proposed some measures for the tourism destination ecosystem. The conclusions include: (a) the requirements of Dunhuang tourism destination ecosystem on the natural ecosystem continuously grew between 2000 and 2012; (b) The sustainable development potential of the Dunhuang tourism destination ecosystem was on an oscillation upward trend during the study period, which is dependent on government attention, and pollution problems were improved.
With less than 6% of total global water resources but one fifth of the global population, China is facing serious challenges for its water resources management, particularly in rural areas due to the long-standing urban-rural dualistic structure and the economic-centralized developmental policies. This paper addresses the key water crises in rural China including potable water supply, wastewater treatment and disposal, water for agricultural purposes, and environmental concerns, and then analyzes the administrative system on water resources from the perspective of characteristics of the current administrative system and regulations; finally, synthetic approaches to solve water problems in rural China are proposed with regard to institutional reform, regulation revision, economic instruments, technology innovation and capacity-building. These recommendations provide valuable insights to water managers in rural China so that they can identify the most appropriate pathways for optimizing their water resources, reducing the total wastewater discharge and improving their water-related ecosystem.
Resource prospects of municipal solid wastes generated in the Ga East Municipal Assembly of Ghana
(2017)
Background: Municipal solid wastes management has recently become an important public health concern. Municipal solid wastes are a major source of raw materials that could be used for resource recovery for diverse applications.
Objectives: The present study aimed to determine the composition of municipal solid waste and recoverable resources from the waste of the Ga East Municipal Assembly (GEMA) in the Greater Accra region of Ghana.
Methods: An exploratory approach was used to collect pertinent data from the Abloradgei dumpsite in GEMA using semi-structured interviews and focus group discussion. A field characterization study was undertaken to segregate and estimate the value of various components of collected waste. Dumpsite workers were asked about current general composition of MSW, mode of collection and disposal, record of sanitation-related diseases, use of modern treatment plant, waste management legislation and enforcement challenges, number of trucks received by the dumpsite per day, record on pretreatment of MSW before disposal, and use of personnel protective equipment.
Results: The results showed that significant proportions (48.8%) of the municipal solid wastes were organic materials, while the remaining (51.2%) were inorganic materials. The results also showed that 63% of the municipal solid waste is collected with no sorting from the source and no modern treatment applied before dumping. It was estimated that the value of the recyclable materials in GEMA municipal solid waste amounts to Ghana Cedis (GH¢) 9,381,960 (plastic); 985,111 (mixed glass); 5,160,078 (paper) and 11,586,770 (metal) with a total of GH¢ 27,113,919 ($10,845,568) equivalent to 2,106,339.2 m3 (74,384,667.5 ft3) per annum of biogas from these components with a market value of GH¢ 1,997,972.17 ($768, 393.62); 11,579 Mwh (1.32 Mw) of electricity and 9,535 Mwh (1.09 Mw) of heat. This is estimated to be lost with the current waste management practices.
Conclusions: We recommend that GEMA institute sustainable recycling practices and utilization of biogas production technologies and prioritize sanitation and waste management education for the public, obligate home segregation of waste materials, involve workers by providing them with protective clothing, incorporate informal waste collectors and scavengers into the new system and collaborate with research institutions in waste-to-resource projects to ensure a more sustainable waste management system in the municipality.
In the single-processor scheduling problem with time restrictions there is one main processor and B resources that are used to execute the jobs. A perfect schedule has no idle times or gaps on the main processor and the makespan is therefore equal to the sum of the processing times. In general, more resources result in smaller makespans, and as it is in practical applications often more economic not to mobilize resources that will be unnecessary and expensive, we investigate in this paper the problem to find the smallest number B of resources that make a perfect schedule possible. We show that the decision version of this problem is NP-complete, derive new structural properties of perfect schedules, and we describe a Mixed Integer Linear Programming (MIP) formulation to solve the problem. A large number of computational tests show that (for our randomly chosen problem instances) only B=3 or B=4 resources are sufficient for a perfect schedule.
The purpose of this article is to evaluate optimal expected utility risk measures (OEU) in a risk-constrained portfolio optimization context where the expected portfolio return is maximized. We compare the portfolio optimization with OEU constraint to a portfolio selection model using value at risk as constraint. The former is a coherent risk measure for utility functions with constant relative risk aversion and allows individual specifications to the investor’s risk attitude and time preference. In a case study with three indices, we investigate how these theoretical differences influence the performance of the portfolio selection strategies. A copula approach with univariate ARMA-GARCH models is used in a rolling forecast to simulate monthly future returns and calculate the derived measures for the optimization. The results of this study illustrate that both optimization strategies perform considerably better than an equally weighted portfolio and a buy and hold portfolio. Moreover, our results illustrate that portfolio optimization with OEU constraint experiences individualized effects, e.g., less risk-averse investors lose more portfolio value in the financial crises but outperform their more risk-averse counterparts in bull markets.
Most of the land reforms of recent decades have followed an approach of “formalization and capitalization” of individual land titles (de Soto 2000). However, within the privatization agenda, benefits of unimproved land (such as land rents and value capture) are reaped privately by well-organized actors, whereas the costs of valorization (e.g., infrastructure) or opportunity costs of land use changes are shifted onto poorly organized groups. Consequences of capitalization and formalization include rent seeking and land grabbing. In developing countries, formal law often transpires to work in favor of the winners of the titling process and is opposed by the customary rights of the losers. This causes a lack of general acknowledgement of formalized law (which is made responsible for deprivation of livelihoods of vulnerable groups) and often leads to a clash of formal and customary norms. Countries may fall into a state of de facto anarchy and “de facto open access”. Encroachment and destruction of natural resources may spread. A reframing of development policy is necessary in order to fight these aberrations. Examples and evidence are provided from Cambodia, which has many features in common with other countries in Asia and Sub-Saharan Africa in this respect.