237 research outputs found

    The relation between culture and Vietnamese entrepreneurship in Norway

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    This study presents an exploratory and quantitative investigation of Norwegian Vietnamese in Norway to explain the Entrepreneurial Orientation and then Entrepreneurship of Vietnamese community in Norway with the emphasis on culture respect. A survey of 190 Norwegian students and 34 Norwegian Vietnamese was conducted online. A comparison between Vietnamese Norwegian and non-immigrant Norwegians was done with reference to the results of previous studies. And from that, the culture dimension values held by Vietnamese Norwegian culture were discovered and used to explain the Entrepreneurial Orientation and Entrepreneurship of the community. The finding is that the Vietnamese Norwegian community lacks some of cultural tendencies that will engender a strong entrepreneurship. Some implications are drawn for ongoing studies

    Removals of sulfonamide and trimethoprim antibiotics in municipal wastewater by biological treatment processes

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    Discharge of treated municipal effluents is an important route for the release of antibiotic pharmaceuticals into the aquatic environment. The occurrence of antibiotics in the environments is of concern due to their potential impact on aquatic species and the possible proliferation of antibiotic resistant strains of bacteria. Although conventional wastewater treatment processes were not designed to eliminate trace chemical contaminants including antibiotics, selection of appropriate treatment processes and optimization of their operational conditions may enhance the removal of many of these substances. A highly sensitive and reliable method using liquid chromatography tandem mass spectrometry was developed for the analysis of six sulfonamide antibiotics (sulfadiazine, sulfamerazine, sulfamethazine, sulfamethoxazole, sulfapyridine and sulfathiazole), two sulfonamide metabolites (N4-acetyl sulfamethazine and N4-acetyl sulfamethoxazole) and the commonly co-applied antibiotic trimethoprim, in aqueous and solid phases of wastewater. The complex wastewater matrices were shown to result in significant and unpredictable signal suppression for the analysis. Correction of such matrix effects was essential in order to achieve accurate quantification, and this was achieved using isotope dilution. Several experiments using controlled laboratory treatment processes were conducted to understand the fundamental removal mechanisms of the selected sulfonamide and trimethoprim antibiotics during biological treatment process. Further laboratory experiments were undertaken to assess the effects of specific design and operational parameters on the removal efficiencies of these antibiotics. Case studies at two full scale wastewater treatment plants were also carried out to confirm the removal trends observed in the lab-scale experiments. Biodegradation was revealed to be the key mechanism for eliminating sulfonamides and trimethoprim during aerobic biological treatment process compared to relatively insignificant removal by sorption to sludge. The removals of sulfonamides by aerobic bioreactors were shown to be consistently greater than that of trimethoprim. During biological treatment, evidence of transformation between sulfonamides and their corresponding N4-acetyl metabolites was observed. The removals of the investigated antibiotics by membrane bioreactors (MBRs) were shown to be as effective as conventional activated sludge treatment. Furthermore, the effective treatment by MBR was shown to be highly robust and stable over a range of operational conditions. These results reveal MBRs to be an effective technology for biological wastewater treatment and a promising alternative to conventional activated sludge treatment

    Bearing-Based Network Localization Under Gossip Protocol

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    This paper proposes a bearing-based network localization algorithm with a randomized gossip protocol. Each sensor node is assumed to be able to obtain the bearing vectors and communicate its position estimates with several neighboring agents. Each update involves two agents, and the update sequence follows a stochastic process. Under the assumption that the network is infinitesimally bearing rigid and contains at least two beacon nodes, we show that the proposed algorithm could successfully estimate the actual positions of the network in probability. The randomized update protocol provides a simple, distributed, and reduces the communication cost of the network. The theoretical result is then supported by a simulation of a 1089-node sensor network.Comment: preprint, 7 pages, 2 figure

    Establishment of Intensity-Duration-Frequency Curves for Precipitation in the Monsoon Area of Vietnam

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    降水の強度-期間-頻度曲線(rainfall Intensity-Duration-Frequency (IDF) relationship)は,水工計画や水工設計,様々な水資源プロジェクトにおいて最も共通に使われる有用なツールである。IDF曲線の構築はBernard(1932)によって初めてなされ,それ以来,多くの関係式が世界中で提案されてきた。しかしながら,そのような関係式を用いた降水の等値線図は,ベトナムを含めてアジアモンスーン域の多くの発展途上国で極めて需要が高いにも関わらず,充分作成されていない。本研究ではベトナムにおける7箇所の降雨観測所におけるIDF曲線を構築し,一般化IDF曲線をベトナム Red River Delta (RRD)を対象に構築する。The rainfall Intensity-Duration-Frequency (IDF) relationship is one of the most commonly used tools in water resources engineering, either for planning, designing and operating of water resource projects, or for various engineering projects against floods. The establishment of such relationships was done as early as in 1932 (Bernard). Since then, many sets of relationships have been constructed for several parts of the globe. However, such map with rainfall intensity contours has not been constructed in many developing countries, including Vietnam. There is a high need for IDF curves in the monsoon region of Vietnam. This research is to construct IDF curves for seven stations in the monsoon area of Vietnam and to propose a generalized IDF formula using base rainfall depth, and base return period for Red River Delta (RRD) of Vietnam.降水の強度-期間-頻度曲線(rainfall Intensity-Duration-Frequency (IDF) relationship)は,水工計画や水工設計,様々な水資源プロジェクトにおいて最も共通に使われる有用なツールである。IDF曲線の構築はBernard(1932)によって初めてなされ,それ以来,多くの関係式が世界中で提案されてきた。しかしながら,そのような関係式を用いた降水の等値線図は,ベトナムを含めてアジアモンスーン域の多くの発展途上国で極めて需要が高いにも関わらず,充分作成されていない。本研究ではベトナムにおける7箇所の降雨観測所におけるIDF曲線を構築し,一般化IDF曲線をベトナム Red River Delta (RRD)を対象に構築する。The rainfall Intensity-Duration-Frequency (IDF) relationship is one of the most commonly used tools in water resources engineering, either for planning, designing and operating of water resource projects, or for various engineering projects against floods. The establishment of such relationships was done as early as in 1932 (Bernard). Since then, many sets of relationships have been constructed for several parts of the globe. However, such map with rainfall intensity contours has not been constructed in many developing countries, including Vietnam. There is a high need for IDF curves in the monsoon region of Vietnam. This research is to construct IDF curves for seven stations in the monsoon area of Vietnam and to propose a generalized IDF formula using base rainfall depth, and base return period for Red River Delta (RRD) of Vietnam

    A Combined Delay-Throughput Fairness Model for Optical Burst Switched Networks

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    Fairness is an important feature of communication networks. It is the distribution, allocation, and provision of approximately equal or equal performance parameters, such as throughput, bandwidth, loss rate, and delay. In an optical burst switched (OBS) network, fairness is considered in three aspects: distance, throughput, and delay. Studies on these three types of fairness have been conducted; however, they have usually been considered in isolation. These fairness types should be considered together to improve the communication performance of the entire OBS network. This paper proposes a combined delay-throughput fairness model, where burst assembly and bandwidth allocation are improved to achieve both delay fairness and throughput fairness at ingress OBS nodes. The delay fairness and throughput fairness indices are recommended as metrics for adjusting the assembly queue length and allocated bandwidth for priority flows. The simulation results showed that delay and throughput fairness could be achieved simultaneously, improving the overall communication performance of the entire OBS network

    A SIMPLE SCALING CHARATERISTICS OF RAINFALL IN TIME AND SPACE TO DERIVE INTENSITY DURATION FREQUENCY RELATIONSHIPS

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    The properties of time and space scale invariance of rainfall are investigated and applied to Intensity-Duration-Frequency (IDF) relationships. The hypothesis of the simple scaling is examined in time and space in Yodo River basin and the simple scaling properties in time are confirmed, which is used to derive IDF relationships for short-duration rainfall of several hours from the statistical characteristics of daily data only. The derived IDF matches well with the one derived from historical observed data. Also, the simple scaling properties in space are examined. It is found that two ranges less than 1000 km 2 and more than 1000 km 2 show different scale properties
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