In order to improve the throughput of cognitive radio(CR), optimization of sensing time and cooperative user allocation for OR-rule cooperative spectrum sensing was investigated in a CR network that includes multiple ...In order to improve the throughput of cognitive radio(CR), optimization of sensing time and cooperative user allocation for OR-rule cooperative spectrum sensing was investigated in a CR network that includes multiple users and one fusion center. The frame structure of cooperative spectrum sensing was divided into multiple transmission time slots and one sensing time slot consisting of local energy detection and cooperative overhead. An optimization problem was formulated to maximize the throughput of CR network, subject to the constraints of both false alarm probability and detection probability. A joint optimization algorithm of sensing time and number of users was proposed to solve this optimization problem with low time complexity. An allocation algorithm of cooperative users was proposed to preferentially allocate the users to the channels with high utilization probability. The simulation results show that the significant improvement on the throughput can be achieved through the proposed joint optimization and allocation algorithms.展开更多
Virtualization is a common technology for resource sharing in data center. To make efficient use of data center resources, the key challenge is to map customer demands （modeled as virtual data center, VDC） to the ph...Virtualization is a common technology for resource sharing in data center. To make efficient use of data center resources, the key challenge is to map customer demands （modeled as virtual data center, VDC） to the physical data center effectively. In this paper, we focus on this problem. Distinct with previous works, our study of VDC embedding problem is under the assumption that switch resource is the bottleneck of data center networks （DCNs）. To this end, we not only propose relative cost to evaluate embedding strategy, decouple embedding problem into VM placement with marginal resource assignment and virtual link mapping with decided source-destination based on the property of fat-tree, but also design the traffic aware embedding algorithm （TAE） and first fit virtual link mapping （FFLM） to map virtual data center requests to a physical data center. Simulation results show that TAE＋FFLM could increase acceptance rate and reduce network cost （about 49% in the case） at the same time. The traffie aware embedding algorithm reduces the load of core-link traffic and brings the optimization opportunity for data center network energy conservation.展开更多
Malaysia has long been involved in the initiative of becoming a high income country by the year 2020. In this essence, fighting and eliminating any means of corruption in the public and private companies have been one...Malaysia has long been involved in the initiative of becoming a high income country by the year 2020. In this essence, fighting and eliminating any means of corruption in the public and private companies have been one of the key challenges in the long run. The globalization of businesses has somehow led to an increase in the number of unethical conduct and hazardous corruption. In the urge to enliven ethics and integrity in a company and among employees, the whole business processes and stakeholders should position code of ethics and integrity at its highest standard. However, can ethics and integrity really increase the company＇s reputation, strengthening its business operations and sustainability, and deliver trust amongst employees and employers？ The objective of this study is to analyze the perceptions of employees on issues pertaining ethics and integrity. The study has been conducted in one of the giant telecommunication companies in Malaysia where a sample of 7,056 employees were the participants involved in the survey. The study has used questionnaires to collect data. The data have then been analysed using the SPSS data analysis software. The findings explained that employees view the company as an ethical place to work where the finance department is deemed to have the highest level of integrity. While in matters of corruption risk areas, there are still practices of bribery. It is also founded that a majority of respondents about 93% agree that the company＇s initiatives are effective in building business integrity and that the level of business ethics and integrity has improved over the last two years. Running a business with ethics and integrity while selecting the fight business partners will create a corporation of ethics, integrity, and anti-corruption.展开更多
基金Project(61471194)supported by the National Natural Science Foundation of ChinaProject(BK20140828)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education,China
文摘In order to improve the throughput of cognitive radio(CR), optimization of sensing time and cooperative user allocation for OR-rule cooperative spectrum sensing was investigated in a CR network that includes multiple users and one fusion center. The frame structure of cooperative spectrum sensing was divided into multiple transmission time slots and one sensing time slot consisting of local energy detection and cooperative overhead. An optimization problem was formulated to maximize the throughput of CR network, subject to the constraints of both false alarm probability and detection probability. A joint optimization algorithm of sensing time and number of users was proposed to solve this optimization problem with low time complexity. An allocation algorithm of cooperative users was proposed to preferentially allocate the users to the channels with high utilization probability. The simulation results show that the significant improvement on the throughput can be achieved through the proposed joint optimization and allocation algorithms.
基金This research was partially supported by the National Grand Fundamental Research 973 Program of China under Grant （No. 2013CB329103）, Natural Science Foundation of China grant （No. 61271171）, the Fundamental Research Funds for the Central Universities （ZYGX2013J002, ZYGX2012J004, ZYGX2010J002, ZYGX2010J009）, Guangdong Science and Technology Project （2012B090500003, 2012B091000163, 2012556031）.
文摘Virtualization is a common technology for resource sharing in data center. To make efficient use of data center resources, the key challenge is to map customer demands （modeled as virtual data center, VDC） to the physical data center effectively. In this paper, we focus on this problem. Distinct with previous works, our study of VDC embedding problem is under the assumption that switch resource is the bottleneck of data center networks （DCNs）. To this end, we not only propose relative cost to evaluate embedding strategy, decouple embedding problem into VM placement with marginal resource assignment and virtual link mapping with decided source-destination based on the property of fat-tree, but also design the traffic aware embedding algorithm （TAE） and first fit virtual link mapping （FFLM） to map virtual data center requests to a physical data center. Simulation results show that TAE＋FFLM could increase acceptance rate and reduce network cost （about 49% in the case） at the same time. The traffie aware embedding algorithm reduces the load of core-link traffic and brings the optimization opportunity for data center network energy conservation.
文摘Malaysia has long been involved in the initiative of becoming a high income country by the year 2020. In this essence, fighting and eliminating any means of corruption in the public and private companies have been one of the key challenges in the long run. The globalization of businesses has somehow led to an increase in the number of unethical conduct and hazardous corruption. In the urge to enliven ethics and integrity in a company and among employees, the whole business processes and stakeholders should position code of ethics and integrity at its highest standard. However, can ethics and integrity really increase the company＇s reputation, strengthening its business operations and sustainability, and deliver trust amongst employees and employers？ The objective of this study is to analyze the perceptions of employees on issues pertaining ethics and integrity. The study has been conducted in one of the giant telecommunication companies in Malaysia where a sample of 7,056 employees were the participants involved in the survey. The study has used questionnaires to collect data. The data have then been analysed using the SPSS data analysis software. The findings explained that employees view the company as an ethical place to work where the finance department is deemed to have the highest level of integrity. While in matters of corruption risk areas, there are still practices of bribery. It is also founded that a majority of respondents about 93% agree that the company＇s initiatives are effective in building business integrity and that the level of business ethics and integrity has improved over the last two years. Running a business with ethics and integrity while selecting the fight business partners will create a corporation of ethics, integrity, and anti-corruption.
