34974507
The citation impacts and citation environments of Chinese journals in mathematics
Based on the citation data of journals covered by the China Scientific and Technical Papers and Citations Database (CSTPCD), we obtained aggregated journal-journal citation environments by applying routines developed specifically for this purpose. Local citation impact of journals is defined as the share of the total citations in a local citation environment, which is expressed as a ratio and can be visualized by the size of the nodes. The vertical size of the nodes varies proportionally to a journal’s total citation share, while the horizontal size of the nodes is used to provide citation information after correction for the within-journal (self-) citations. In the “citing” environment, the equivalent of the local citation performance can also be considered as a citation activity index. Using the “citing” patterns as variables one is able to map how the relevant journal environments are perceived by the collective of authors of a journal, while the “cited” environment reflects the impact of journals in a local environment. In this study, we analyze citation impacts of three Chinese journals in mathematics and compare local citation impacts with impact factors. Local citation impacts reflect a journal’s status and function better than (global) impact factors. We also found that authors in Chinese journals prefer international instead of domestic ones as sources for their citations.
19223951
A comparison between the China Scientific and Technical Papers and Citations Database and the Science Citation Index in terms of journal hierarchies and interjournal citation relations
The journal structure in the China Scientific and Technical Papers and Citations Database (CSTPCD) is analysed from three perspectives: the database level, the specialty level and the institutional level (i.e., university journals versus journals issued by the Chinese Academy of Sciences). The results are compared with those for (Chinese) journals included in the Science Citation Index. The frequency of journal-journal citation relations in the CSTPCD is an order of magnitude lower than in the SCI. Chinese journals, especially high-quality journals, prefer to cite international journals rather than domestic ones. However, Chinese journals do not get an equivalent reception from their international counterparts. The international visibility of Chinese journals is low, but varies among fields of science. Journals of the Chinese Academy of Sciences (CAS) have a better reception in the international scientific community than university journals.
6453262
Are the contributions of China and Korea upsetting the world system of science?
SummaryInstitutions and their aggregates are not the right units of analysis for developing a science policy with cognitive goals in view. Institutions, however, can be compared in terms of their performance with reference to their previous stages. King's (2004) 'The scientific impact of nations' has provided the data for this comparison. Evaluation of the data from this perspective along the time axis leads to completely different and hitherto overlooked conclusions: a new dynamic can be revealed which points to a group of emerging nations. These nations do not increase their contributions marginally, but their national science systems grow endogenously. In addition to publications, their citation rates keep pace with the exponential growth patterns, albeit with a delay. The center of gravity of the world system of science may be changing accordingly.
6088061
Analysis of Welding Defects in Spot Welding Process U-I Curves
High speed collecting and managing system of spot welding signal can achieve the A/D conversion and data collection. The data of welding current, electrode voltage as well as welding cycle has been collected. Subsequently, they were processed with data acquisition and memory module, wavelet filtering of digit signal module, U-I curves and energy analyzing module, respectively. Based on the collections of welding current and electrode voltage, a criterion splash occurrence and the defective of loose weld by U-I curves change and acreage were proposed. The results prove that the criterion can decipher the welding splash and defective of loose weld accurately.
14589917
Frequent value compression in packet-based NoC architectures
The proliferation of Chip Multiprocessors (CMPs) has led to the integration of large on-chip caches. For scalability reasons, a large on-chip cache is often divided into smaller banks that are interconnected through packet-based Network-on-Chip (NoC). With increasing number of cores and cache banks integrated on a single die, the on-chip network introduces significant communication latency and power consumption. In this paper, we propose a novel scheme that exploits Frequent Value compression to optimize the power and performance of NoC. Our experimental results show that the proposed scheme reduces the router power by up to 16.7%, with CPI reduction as much as 23.5% in our setting. Comparing to the recent zero pattern compression scheme, the frequent value scheme saves up to 11.0% more router power and has up to 14.5% more CPI reduction. Hardware design of the FV table and its overhead are also presented.
6645019
An Energy Reporting Aggregation Method Based on EAFM and DTRM in WSN
Analyzed the energy consumption disciplinarian of the nodes in WSN, the node’s Energy Attenuation Forecast Model(EAFM) can be established. A Difference-threshold Reporting Mechanism (DTRM) is used to report the residual energy of nodes. The energy collection mechanism based on EAFM and DTRM can reduce energy data reporting times significantly,improve the efficient of energy data collection, save the node's energy at the same time. The experiments in the platform of telosb nodes show that the predicable rate is between 70% and85%, and this method can extend the node’s life by 1% ~ 4.5%.
13798358
A durable and energy efficient main memory using phase change memory technology
Using nonvolatile memories in memory hierarchy has been investigated to reduce its energy consumption because nonvolatile memories consume zero leakage power in memory cells. One of the difficulties is, however, that the endurance of most nonvolatile memory technologies is much shorter than the conventional SRAM and DRAM technology. This has limited its usage to only the low levels of a memory hierarchy, e.g., disks, that is far from the CPU.
 In this paper, we study the use of a new type of nonvolatile memories -- the Phase Change Memory (PCM) as the main memory for a 3D stacked chip. The main challenges we face are the limited PCM endurance, longer access latencies, and higher dynamic power compared to the conventional DRAM technology. We propose techniques to extend the endurance of the PCM to an average of 13 (for MLC PCM cell) to 22 (for SLC PCM) years. We also study the design choices of implementing PCM to achieve the best tradeoff between energy and performance. Our design reduced the total energy of an already low-power DRAM main memory of the same capacity by 65%, and energy-delay2 product by 60%. These results indicate that it is feasible to use PCM technology in place of DRAM in the main memory for better energy efficiency.
2961354
On Adding Link Dimensional Dynamism to CSMA/CA Based MAC Protocols
Though the popular IEEE 802.11 DCF is designed primarily for wireless LAN (WLAN) environments, today it is being widely used for wide area wireless mesh networking. The protocol parameters of IEEE 802.11 such as timeout values, interframe spaces, and slot durations, which are sufficient for a general WLAN environment need to be modified in order to efficiently operate in wide area wireless mesh networks. The current wide area wireless mesh network deployments use manual configuration of these parameters to the upper limit which essentially makes the networks operate at lower system efficiency. In this paper, we propose d802.11 (dynamic 802.11) which dynamically adapts the protocol parameters in order to operate at varying link distances. We present three strategies, (i) multiplicative timer back-off (MTB), (ii) additive timer back-off (ATB), and (iii) link RTT memorization (LRM), to adapt the ACK_TIMEOUT in d802.11 in order to provide better adaptation for varying link dimensions. Through extensive simulation experiments we observed significant performance improvement for the proposed strategies. We also theoretically modeled the maximum throughput as a function of the link dimension for the proposed system. Our results show that the LRM technique provides the best adaptation compared to all other schemes.