There are essentially six sources for obsidians in the Mediterranean Basin： Mount Arci in Sardinia, the islands of Lipari and Pantelleria in Sicily and Palmarola in Latium, as well as the islands of Melos and Gyali i...There are essentially six sources for obsidians in the Mediterranean Basin： Mount Arci in Sardinia, the islands of Lipari and Pantelleria in Sicily and Palmarola in Latium, as well as the islands of Melos and Gyali in the south-eastern part of Greece. Identification and quantification of principal and trace elements which compose this volcanic glass allow source tracking. The present study proposes a investigation methodology, which was developed on a sample set composed by archaeological obsidian findings from Neolithic sites in Latium; three different analytical techniques are compared： SEM-EDXS, ED-XRF and LA-ICP-MS, in order to gather a wide data set to be compared with data in literature and to be processed by Principal Component Analysis （PCA） for assigning a provenance to each find.展开更多
Based on the theory of Fuzzy Mathematics and Expert System, this paper presents the quantitative expression method of bedded and joint bearing rock mass quality "Stratum Quality Index"(SQI for short), and al...Based on the theory of Fuzzy Mathematics and Expert System, this paper presents the quantitative expression method of bedded and joint bearing rock mass quality "Stratum Quality Index"(SQI for short), and also introduces the successful application of the method in estimating stratum movement parameters.展开更多
This paper analyzes the basic interactivity connotation of network teaching from the interactive definition, function, types and level etc., and established the interaction quality evaluation index system from the fou...This paper analyzes the basic interactivity connotation of network teaching from the interactive definition, function, types and level etc., and established the interaction quality evaluation index system from the four angles between student and media, the course content, teacher and peer interaction. Similarly, network instruction interaction also needs to carry on the design from the perspective of instructional design, and take full advantage of the Internet, and finally achieved good network interaction effect. Practice shows that, research on network interactive strategy significance.展开更多
The new measurement scheme of IP performance metrics is for the mobile network in heterogeneous wireless network environment. In the proposed scheme, when Mobile Nodes （MNs） inside the mobile network needs to under...The new measurement scheme of IP performance metrics is for the mobile network in heterogeneous wireless network environment. In the proposed scheme, when Mobile Nodes （MNs） inside the mobile network needs to understand the condition of multiple comrmunicatinn paths outside the mobile netwtrk, they can get IP performance metrics, such as delay, jitter, bandwidth, packet loss, etc., irrespective of the preserre or absence of measurement functionality. At the same time, the proposed scheme dees not require the MN to he involved in measuring IP performance metrice. The Multihomed Mobile Router （MMR） with heterogeneons wireless interfaces measures IP performance metrics on behalf of the MNs inside the mobile network. Then, MNs can get measured IP perfonmnce metries from the MMR using L3 messages. The proposed scheme can reduce burden and power consumption of MNs with limited resource and batty power since MNs don＇ t measure IP performance metrics directly. In addition, it can reduce considerably traffic overhead over wireless links on multiple measurement paths since signaling messages and injeeted testing traffic are reduced.展开更多
The occurrence of bumper or poor grain harvests in ancient China plays an important role in explaining how past climate changes affected the economy.Because of the lack of long-term continuous and high-resolution quan...The occurrence of bumper or poor grain harvests in ancient China plays an important role in explaining how past climate changes affected the economy.Because of the lack of long-term continuous and high-resolution quantitative data for reconstructing the series of grain harvests in ancient China,understanding of the impacts and mechanisms involved in climate change is limited.This study presents a method designed for reconstructing grain harvest series by quantifying grain output levels based on the descriptions in historical documents.The method involves setting the grain output level for each year based on very specific meanings of different words,calculating a yield index based on the structure of each level and assessing grain yields(bumper or poor harvests)every 10 years.First,1636 records related to grain yields(including crop yields,food security,agricultural disasters,grain prices,grain storage and people's livelihoods)for each year were retrieved from history books called the Twenty-Four Histories.Second,using this method,a 10-year resolution graded grain harvest series from the Western Han Dynasty to the Five Dynasties(206 BC–960 AD)is reconstructed.Finally,the relationship between the variations in temperature and precipitation and the fluctuation of grain yields is examined.The results show that from the Western Han Dynasty to the Five Dynasties,bumper,average and poor harvest decades accounted for 33.3%,39.3%and 27.4%of the 1,166-year period,respectively.The grain yields during 206 BC–960 AD can be divided into three stages:a period of bumper harvests during 206–51 BC,poor harvests during 50 BC–590 AD and bumper harvests during 591–960 AD.Bumper harvest decades typically experienced a warm climate with normal or high levels of precipitation,while poor harvest decades had a cold and dry climate.A positive correlation was found between temperature and grain yield because a warm climate allows a full use of resources.The observed relationship between precipitation and grain yield indicated that both flooding and droughts cause poor harvests,which confirms that agricultural production in the monsoon climate of eastern China is greatly impacted by conditions of limited heat and extreme precipitation.展开更多
文摘There are essentially six sources for obsidians in the Mediterranean Basin： Mount Arci in Sardinia, the islands of Lipari and Pantelleria in Sicily and Palmarola in Latium, as well as the islands of Melos and Gyali in the south-eastern part of Greece. Identification and quantification of principal and trace elements which compose this volcanic glass allow source tracking. The present study proposes a investigation methodology, which was developed on a sample set composed by archaeological obsidian findings from Neolithic sites in Latium; three different analytical techniques are compared： SEM-EDXS, ED-XRF and LA-ICP-MS, in order to gather a wide data set to be compared with data in literature and to be processed by Principal Component Analysis （PCA） for assigning a provenance to each find.
文摘Based on the theory of Fuzzy Mathematics and Expert System, this paper presents the quantitative expression method of bedded and joint bearing rock mass quality "Stratum Quality Index"(SQI for short), and also introduces the successful application of the method in estimating stratum movement parameters.
文摘This paper analyzes the basic interactivity connotation of network teaching from the interactive definition, function, types and level etc., and established the interaction quality evaluation index system from the four angles between student and media, the course content, teacher and peer interaction. Similarly, network instruction interaction also needs to carry on the design from the perspective of instructional design, and take full advantage of the Internet, and finally achieved good network interaction effect. Practice shows that, research on network interactive strategy significance.
文摘The new measurement scheme of IP performance metrics is for the mobile network in heterogeneous wireless network environment. In the proposed scheme, when Mobile Nodes （MNs） inside the mobile network needs to understand the condition of multiple comrmunicatinn paths outside the mobile netwtrk, they can get IP performance metrics, such as delay, jitter, bandwidth, packet loss, etc., irrespective of the preserre or absence of measurement functionality. At the same time, the proposed scheme dees not require the MN to he involved in measuring IP performance metrice. The Multihomed Mobile Router （MMR） with heterogeneons wireless interfaces measures IP performance metrics on behalf of the MNs inside the mobile network. Then, MNs can get measured IP perfonmnce metries from the MMR using L3 messages. The proposed scheme can reduce burden and power consumption of MNs with limited resource and batty power since MNs don＇ t measure IP performance metrics directly. In addition, it can reduce considerably traffic overhead over wireless links on multiple measurement paths since signaling messages and injeeted testing traffic are reduced.
基金supported by the Major State Basic Research Development Program of China (973 Program) (Grant No. 2010CB950103)National Natural Science Foundation of China (Grant No. 41071127)Strategic Project of Science and Technology of the Chinese Academy of Sciences (Grant No. XDA05080102)
文摘The occurrence of bumper or poor grain harvests in ancient China plays an important role in explaining how past climate changes affected the economy.Because of the lack of long-term continuous and high-resolution quantitative data for reconstructing the series of grain harvests in ancient China,understanding of the impacts and mechanisms involved in climate change is limited.This study presents a method designed for reconstructing grain harvest series by quantifying grain output levels based on the descriptions in historical documents.The method involves setting the grain output level for each year based on very specific meanings of different words,calculating a yield index based on the structure of each level and assessing grain yields(bumper or poor harvests)every 10 years.First,1636 records related to grain yields(including crop yields,food security,agricultural disasters,grain prices,grain storage and people's livelihoods)for each year were retrieved from history books called the Twenty-Four Histories.Second,using this method,a 10-year resolution graded grain harvest series from the Western Han Dynasty to the Five Dynasties(206 BC–960 AD)is reconstructed.Finally,the relationship between the variations in temperature and precipitation and the fluctuation of grain yields is examined.The results show that from the Western Han Dynasty to the Five Dynasties,bumper,average and poor harvest decades accounted for 33.3%,39.3%and 27.4%of the 1,166-year period,respectively.The grain yields during 206 BC–960 AD can be divided into three stages:a period of bumper harvests during 206–51 BC,poor harvests during 50 BC–590 AD and bumper harvests during 591–960 AD.Bumper harvest decades typically experienced a warm climate with normal or high levels of precipitation,while poor harvest decades had a cold and dry climate.A positive correlation was found between temperature and grain yield because a warm climate allows a full use of resources.The observed relationship between precipitation and grain yield indicated that both flooding and droughts cause poor harvests,which confirms that agricultural production in the monsoon climate of eastern China is greatly impacted by conditions of limited heat and extreme precipitation.
