Erasure code is widely used as the redundancy scheme in distributed storage system. When a storage node fails, the repair process often requires to transfer a large amount of data. Regenerating code and hierarchical c...Erasure code is widely used as the redundancy scheme in distributed storage system. When a storage node fails, the repair process often requires to transfer a large amount of data. Regenerating code and hierarchical code are two classes of codes proposed to reduce the repair bandwidth cost. Regenerating codes reduce the amount of data transferred by each helping node, while hierarchical codes reduce the number of nodes participating in the repair process. In this paper, we propose a "sub-code nesting framework" to combine them together. The resulting regenerating hierarchical code has low repair degree as hierarchical code and lower repair cost than hierarchical code. Our code can achieve exact regeneration of the failed node, and has the additional property of low updating complexity.展开更多
The background and purpose, and the current situation of the cost control theory of real estate development project are disscussed in the paper. Problems of cost control for real estate development projects in China a...The background and purpose, and the current situation of the cost control theory of real estate development project are disscussed in the paper. Problems of cost control for real estate development projects in China are analyzed and summarized. According to the real estate development project cost control problems and related factors, a cost control index system of real estate development enterprise, and a cost control factors index system of real estate projects are constructed respectively. Cost control in the five stages of a real estate development project is introduced and summarized respectively. The five stages include: the investment decision-making, planning and design stage, the bidding phase, project implementation stage, and rental or sale.展开更多
This work aims at exploring the effects of the interconnection between isolated electric power systems upon some important aspects such as enhancing reliability levels along with reducing installation and operation co...This work aims at exploring the effects of the interconnection between isolated electric power systems upon some important aspects such as enhancing reliability levels along with reducing installation and operation costs. To discern the advantages associated with this study, the developed methodology has been applied to three existing power systems in the northern region of the Kingdom of Saudi Arabia presently within the concession domain of the Saudi Electric Company (SEC). These systems have been established to meet the present loads and to withstand future electrical demands for a period of time before additional generation and transmission reinforcements are needed. In this work, reliability measures have been utilized to determine the period that these systems can fulfill the present and future loads without affecting the reliability levels and the threshold that an additional capacity should be added to maintain those required reliability levels. In application to the reliability criteria, technical, operational and economic advantages can be realized, i.e., higher reliability levels and lower installation and operation costs after the proposed interconnection between these selected isolated power systems take place.展开更多
基金Supported by 973 Project of China (No. 2012CB315803)Research Fund for the Doctoral Program of Higher Education of China (No. 20100002110033)Open research Fund of National Mobile Communications Research Laboratory, Southeast University (No. 2011D11)
文摘Erasure code is widely used as the redundancy scheme in distributed storage system. When a storage node fails, the repair process often requires to transfer a large amount of data. Regenerating code and hierarchical code are two classes of codes proposed to reduce the repair bandwidth cost. Regenerating codes reduce the amount of data transferred by each helping node, while hierarchical codes reduce the number of nodes participating in the repair process. In this paper, we propose a "sub-code nesting framework" to combine them together. The resulting regenerating hierarchical code has low repair degree as hierarchical code and lower repair cost than hierarchical code. Our code can achieve exact regeneration of the failed node, and has the additional property of low updating complexity.
文摘The background and purpose, and the current situation of the cost control theory of real estate development project are disscussed in the paper. Problems of cost control for real estate development projects in China are analyzed and summarized. According to the real estate development project cost control problems and related factors, a cost control index system of real estate development enterprise, and a cost control factors index system of real estate projects are constructed respectively. Cost control in the five stages of a real estate development project is introduced and summarized respectively. The five stages include: the investment decision-making, planning and design stage, the bidding phase, project implementation stage, and rental or sale.
文摘This work aims at exploring the effects of the interconnection between isolated electric power systems upon some important aspects such as enhancing reliability levels along with reducing installation and operation costs. To discern the advantages associated with this study, the developed methodology has been applied to three existing power systems in the northern region of the Kingdom of Saudi Arabia presently within the concession domain of the Saudi Electric Company (SEC). These systems have been established to meet the present loads and to withstand future electrical demands for a period of time before additional generation and transmission reinforcements are needed. In this work, reliability measures have been utilized to determine the period that these systems can fulfill the present and future loads without affecting the reliability levels and the threshold that an additional capacity should be added to maintain those required reliability levels. In application to the reliability criteria, technical, operational and economic advantages can be realized, i.e., higher reliability levels and lower installation and operation costs after the proposed interconnection between these selected isolated power systems take place.
