The relationships between electrical conductivity of soil and reflectance of canopy,grain, and leaf of rice in northeastern Thailand

Soil salinity is a global environmental problem and the most widespread land degradation problem that reduces crop yields and agricultural productivity. The characteristic of soil salinity is conventionally measured by the electric conductivity (EC) of soil while remote-sensing techniques have been extensively applied to detect the presence of salts indirectly through the vegetation using crop spectral reflectance. This study aims primarily to investigate whether salt stress the rice can be detected by field reflectance or not, and second, to search the significant bands of vegetation indices that can indicate the relationships between the EC of soil and field hyperspectral reflectance of canopy, grain, and leaf of rice, using the normalized difference spectral index (NDSI). Field investigations on various paddy fields in northeastern Thailand were carried out in late November 2010 during the ripening season just before harvest in an attempt to realize the applications of the field hyperspectral technique for monitoring the spread of saline soils and estimation of the effects of soil salinity on rice plants. Jasmine rice and glutinous rice were two different rice species selected for this study. Rice plant investigations were conducted by collecting data on crop length, panicle length, canopy openness, leaf area index, and digital photographs of plant conditions from each site. The statistical analysis revealed that the changes in soil EC were significantly sensitive to the ripening stages of both jasmine rice and glutinous rice planted on different levels of soil salinity. Among reflectance measurements, canopy reflectance was highly correlated with soil EC. However, the estimated accuracies of the relationship between soil EC and reflectance of glutinous rice were relatively lower than those of jasmine rice.     

Guest Editorial: Selected Papers on Wireless and Mobility from IEEE INFOCOM

The three papers in this special section were originally presented at the IEEE INFOCOM 2006 conference in Barcelona. The augmented papers, which address issues in wireless networks and mobile computing, represent the high quality of research presented at the conference.     

Modeling the performance of HTTP over several transport protocols

This paper considers the interaction of HTTP with several transport protocols, including TCP, Transaction TCP, a UDP-based request-response protocol, and HTTP with persistent TCP connections. We present an analytic model for each of these protocols and use that model to evaluate network overhead carrying HTTP traffic across a variety of network characteristics. This model includes an analysis of the transient effects of TCP slow-start. We validate this model by comparing it to network packet traces measured with two protocols (HTTP and persistent HTTP) over local and wide-area networks. We show that the model is accurate within 5% of measured performance for wide-area networks, but can underestimate latency when the bandwidth is high and delay is low. We use the model to compare the connection-setup costs of these protocols, bounding the possible performance improvement. We evaluate these costs for a range of network characteristics, finding that setup optimizations are relatively unimportant for current modem, ISDN, and LAN users but can provide moderate to substantial performance improvement over high-speed WANs. We also use the model to predict performance over future network characteristics     

Open dumping site in Asian developing countries: a potential source of polychlorinated dibenz-p-dioxins and polychlorinated dibenzofurans

Open landfill dumping areas for municipal wastes in Asian developing countries have recently received particular attention with regard to environmental pollution problems. Because of the uncontrolled burning of solid wastes, elevated contamination by various toxic chemicals including dioxins and related compounds in these dumping sites has been anticipated. In this study, concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (PCBs) were determined in soils from dumping sites in the Philippines, Cambodia, India, and Vietnam. Residue concentrations of PCDD/Fs and coplanar PCBs in dumping site soils were apparently greater than those in soils collected in agricultural or urban areas far from dumping sites, suggesting that dumping sites are potential sources of PCDD/Fs and related compounds. Observed PCDD/F concentrations in soils from dumping sites in the Philippines and Cambodia were comparable or higher than those reported for dioxin-contaminated locations in the world (e.g., near the municipal waste incinerators and open landfill dumping sites). Homologue profiles of PCDD/Fs in dumping site soils from the Philippines and, to a lesser extent, from Cambodia and India reflected patterns of samples representing typical emissions, while profiles of agricultural or urban soils were similar to those of typical environmental sinks. This result suggests recent formation of PCDD/Fs in dumping site areas and that open dumping sites are a potential source of dioxins in Asian developing countries. Uncontrolled combustions of solid wastes by waste pickers, generation of methane gas, and low-temperature burning can be major factors for the formation of dioxins in dumping sites. Elevated fluxes of PCDD/Fs to soils in dumping sites were encountered in the Philippines, Cambodia, India, and Vietnam-Hanoi, and these levels were higher than those reported for other countries. Considerable loading rates of PCDD/Fs in the dumping sites of these countries were observed, ranging from 20 to 3900 mg/yr (0.12-35 mg TEQ/yr). PCDD/F concentrations in some soil samples from the Philippines, Cambodia, India, and Vietnam-Hanoi exceeded environmental guideline values, suggesting potential health effects on humans and wildlife living near these dumping sites. The estimated intakes of dioxins via soil ingestion and dermal exposure for children were higher than those for adults, suggesting greater risk of dioxin exposure for children in dumping sites. To our knowledge, this is the first comprehensive study on PCDD/Fs contamination in open dumping sites of Asian developing countries. On the basis of the result of this study, we have addressed a new environmental issue that open dumping sites are potential sources of PCDD/Fs and related compounds, and dioxin contamination in dumping sites may become a key environmental problem in developing countries.     

Report and discussion on the IEEE ComSoc TCGN Gigabit NetworkingWorkshop 1995

Presents a summary of the second Gigabit Networking Workshop. The focus of the workshop is on end-to-end (level 4) and higher issues. Topics discussed include: ATM and B-ISDN, TCP/IP over ATM, ATM role in the future Internet-based Global Information Infrastructure, traffic monitoring and middleware     

Telecommunications issues of intelligent database management for ground processing systems in the EOS era

Future NASA Earth science missions, including the Earth Observing Systems (EOS), will generate vast amounts of data that must be processed and stored at various locations around the world. This article presents a stepwise-refinement of the Intelligent Database Management (IDM) system of the Distributed Active Archive Center (DAAC-one of seven regionally-located EOSDIS archive sites) architecture to showcase the telecommunications issues involved. This architecture is developed into a general overall design. It is shown that the current evolution of protocols is sufficient to support IDM at Gbps rates over large distances. It is also shown that the network design can accomodate o flexible data ingestion storage pipeline and a user extraction visualization engine, without interference between the two.     

Defining high-speed protocols: five challenges and an example thatsurvives the challenges

The First IEEE Gigabit Networking (GBN) Workshop defined a set of characteristics of “Interesting” high-speed applications. The GBN criteria ensure that the application addresses a significant problem, and that it actually requires a gigabit network. This paper presents five challenges that augment the GBN criteria. These challenges ask whether gigabit applications require new research into different protocols, or can be supported by existing protocols that merely run faster. It shows a class of applications, interactive distributed multimedia, namely interactive real-time World Wide Web (WWW) access, that survive the challenges. It also shows how source presenting is a way to use excess bandwidth-delay product to reduce the browser response time, and how this is one example of a truly gigabit protocol     

High-speed data paths in host-based routers

In networking today, host workstations are increasingly being used as routers. Host based routers offer a number of advantages, but they suffer from inefficient support for high bandwidth interfaces. The authors' work has focused on the technology's major drawback its inefficiency in supporting high bandwidth interfaces. Their approach is to optimize packet processing by applying techniques that transfer packets directly among host interfaces, thus removing an extra data copy. This technique increases data throughput by 45 percent while reducing the host's CPU load. They found that peer DMA forwarding can increase host based router throughput by up to 45 percent, supporting bandwidths of 480 Mbps. Peer DMA host based forwarding requires network interface cards with substantial shared memory resources, because packet queues are stored on the interfaces themselves, rather than in host RAM. The queuing algorithm remains in the host CPU, supporting advanced queue management. Current systems have limited packet processing. A combination of streamlined forwarding algorithms and aggregate interrupt processing should further increase host based capability. Moving some of the IP processing out to the NIC coprocessor may enable this. It is also apparent that as processor speeds increase, the advantages of peer DMA will aid throughput for small packet sizes     

Asian Mussel Watch Program: contamination status of polybrominated diphenyl ethers and organochlorines in coastal waters of Asian countries

Mussel samples were used in this study to measure the levels of polybrominated diphenyl ethers (PBDEs) and organochlorines (OCs) in the coastal waters of Asian countries like Cambodia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, the Philippines, and Vietnam. PBDEs were detected in all the samples analyzed, and the concentrations ranged from 0.66 to 440 ng/g lipid wt. Apparently higher concentrations of PBDEs were found in mussels from the coastal waters of Korea, Hong Kong, China, and the Philippines, which suggests that significant sources of these chemicals exist in and around this region. With regard to the composition of PBDE congeners, BDE-47, BDE-99, and BDE-100 were the dominant congeners in most of the samples. Among the OCs analyzed, concentrations of DDTs were the highest followed by PCBs > CHLs > HCHs > HCB. Total concentrations of DDTs, PCBs, CHLs, and HCHs in mussel samples ranged from 21 to 58 000, 3.8 to 2000, 0.93 to 900, and 0.90 to 230 ng/g lipid wt., respectively. High levels of DDTs were found in mussels from Hong Kong, Vietnam, and China; PCBs were found in Japan, Hong Kong, and industrialized/urbanized locations in Korea, Indonesia, the Philippines, and India; CHLs were found in Japan and Hong Kong; HCHs were found in India and China. These countries seem to play a role as probable emission sources of corresponding contaminants in Asia and, in turn, may influence their global distribution.