Online Energy Generation Scheduling for Microgrids with Intermittent Energy Sources and Co-Generation

Microgrids represent an emerging paradigm of future electric power systems that can utilize both distributed and centralized generations. Two recent trends in microgrids are the integration of local renewable energy sources (such as wind farms) and the use of co-generation (i.e., to supply both electricity and heat). However, these trends also bring unprecedented challenges to the design of intelligent control strategies for microgrids. Traditional generation scheduling paradigms rely on perfect prediction of future electricity supply and demand. They are no longer applicable to microgrids with unpredictable renewable energy supply and with co-generation (that needs to consider both electricity and heat demand). In this paper, we study online algorithms for the microgrid generation scheduling problem with intermittent renewable energy sources and co-generation, with the goal of maximizing the cost-savings with local generation. Based on the insights from the structure of the offline optimal solution, we propose a class of competitive online algorithms, called CHASE (Competitive Heuristic Algorithm for Scheduling Energy-generation), that track the offline optimal in an online fashion. Under typical settings, we show that CHASE achieves the best competitive ratio among all deterministic online algorithms, and the ratio is no larger than a small constant 3.Comment: 26 pages, 13 figures. It will appear in Proc. of ACM SIGMETRICS, 201

Operative strategy for large brain abscess resulting from immune reconstitution inflammatory syndrome in an AIDS patient in Swaziland

SummaryThe objective of our study was to report a rare case with a large brain abscess related to central nervous system immune reconstitution inflammatory syndrome (IRIS) and to discuss the operative strategy for it. Brain abscess with HIV co-infection is considered to be a critical infectious condition that requires neurosurgical intervention. The presentation of IRIS may worsen the patient’s condition after the initiation of antiretroviral therapy, especially in IRIS of the central nervous system. Only a few cases of IRIS-related brain abscess have been reported in the current literature, with discussion of the operative strategy. A 30-year-old man was diagnosed with HIV infection in 2007 and he developed right-sided convulsion episodes in 2008. His first brain computed tomography (CT) scan revealed two intracranial cysts, and his symptoms were well controlled by anticonvulsant treatment. He also initiated antiretroviral therapy in the same year. However, his neurological conditions gradually worsened with sensory loss, weakness, visual impairment on the right side, as well as motor aphasia. A CT scan in 2011 revealed a well-encapsulated, hypodense 8 cm × 9 cm intracranial lesion in the left frontal parietal lobe with a 3-cm midline shift. Surgery was performed with a combination of direct suction and quick-suturing of the incision. The abscess capsule was enucleated completely. After surgical removal, he recovered well and remains functional at work in the following year with only minor neurological sequelae. In conclusion, this case illustrates well the clinical course of brain abscess resulting from IRIS in Swaziland, where the prevalence rate of HIV infection is relatively high and delay in diagnosis and treatment is common. The use of a modified excision method for HIV co-infection brain abscess may be considered the operative strategy, with a probable good outcome in such a resource-limited area as Swaziland

The Effect of Service Quality, Customer Perceived Value and Satisfaction on Loyalty

The service industry has become more and more important for business activities. Service industry contributes about 60% of the annual GDP and 70% of new jobs in America. According to the statistics of Executive Yuan of Taiwan, the service industry contributes over 70% of the annual GDP in 2008. The ultimate goal for companies is to build customer loyalty. With loyal customers, companies can reduce the operating cost and acquisition expenses. An improvement of 5 percent in customer retention leads to an increase of 25 percent to 75 percent in profit. It costs more than five times as much to obtain a new customer than to keep an existing one. This initial study was from relevant literature, then set up research structure and hypotheses. Survey was employed, and respondents were from the customers of TKEC in Taipei area. There were 199 usable questionnaires to analyze descriptive statistics, reliability, validity, and SEM model. The research found that service quality significantly affects customer perceived value and customer satisfaction, and customer perceived value and customer satisfaction have strong impact on customer loyalty for the sample. Therefore, firms have to specifically focus on these factors in order to build a long-term and mutually profitability relationship with a customer and create loyalty as competitive advantages in the market

An Empirical Study of Corporate Brand Image, Customer Perceived Value and Satisfaction on Loyalty in Shoe Industry

A positive corporate brand image is not only increasing competition but also encourage consumers to repurchase. With loyal customers, companies can reduce the operating cost and acquisition expenses. This initial study was from relevant literature, then set up research structure and hypotheses. Survey was employed, and respondents collected from the customers of ASO in Taiwan. There were 208 usable questionnaires to analyze descriptive statistics, reliability, validity, and SEM model. Based on the research results, corporate brand image significantly affects customer perceived value, customer satisfaction and loyalty; customer perceived value has strong impact on customer satisfaction and loyalty for the sample; and customer satisfaction significantly affects customer loyalty. Therefore, companies should have a positive brand image to customers, and specifically focus on those factors in order to build a long-term and mutually profitability relationships with customers and create loyalty as competitive advantages in the markets. The study focuses on the industry of shoes in Taiwan, and adopts only a quantitative method. Future research could employ a different design to examine the causal relationships posited by the theories, and extension the study to discuss mediation or moderation among dimensions

A Green Peel on STEAM Education: An Innovative and Sustainable Education Scheme Integrating STEAM and Environmental Education

The STEAM education in China started late so it is still in its infancy. Its curriculum is partial to IT and Internet, which is against the original purpose of interdisciplinary education in STEAM. Meanwhile, the resources put on environmental education are minute so the environmental awareness of citizens is very weak. Therefore, we have proposed an innovative education scheme—integrating STEAM, environmental and family education together so that they can complement each other. Such a scheme not only makes STEAM education more comprehensive, it can also make environmental education more effective. To implement our scheme, we have made use of peel wastes to produce a new natural peel crayon. The whole production process is further developed to a curriculum which serves as an education model that combines all five elements in STEAM education. Together we have created a ‘learning package’ that takes care of students’ individuality in education. After putting it into practice, we have received positive feedbacks from both parents and children. Furthermore, we have done several standard tests to ensure the safety of our peel crayons. Results have proved the feasibility of our new education scheme. Such a scheme has provided a role model for integration of environmental and STEAM education. In the future, we hope to develop more education models to make our learning package more diverse and applied in different aspects