contain several IP-enabled devices, such as Earth observing equipment, that will be accessible by... more contain several IP-enabled devices, such as Earth observing equipment, that will be accessible by terrestrial users through the Internet. Mobility solutions, such as Mobile IPv6, can be used to handle the mobility of individual devices as the spacecraft moves around the Earth and handsover between ground stations. Mobility management of individual hosts, however, results in large amount of signaling in the bandwidth-limited satellite links and manageability problem as the number of devices increases. Network Mobility (NEMO) protocols can be used for mobility management of such a group of devices moving together. In this paper, we propose an architecture for application of NEMO in satellite networks, where the devices are connected using an on-board Local Area Network. In addition to providing continuous connectivity between onboard devices from Earth, the architecture enjoys several advantages, such as reduced signaling, increased manageability and conservation of satellite link ban...
International Journal of Fisheries and Aquatic Studies, 2018
A yearlong study was conducted to observe the present status of integrated aquaculture in Nilpham... more A yearlong study was conducted to observe the present status of integrated aquaculture in Nilphamari district of Bangladesh. Data were collected from 76 farmers using a questionnaire. Three different types of integrated aquaculture systems were observed: rice-fish culture (46%), fish-horticulture (33%), and fish-poultry culture (21%). Fishes were cultured in polyculture systems. Banana, papaya, vegetables etc. were planted in pond dikes. Other important findings were: age of most farmers (76%) between 41 and 60 years, the highest percentage of educational qualification class eight (40%), trained farmers (66%), and average farm size 0.29 ha. Major problems were low water retention capacity of the soil, lack of quality seeds, lack of capital, high labor cost, insufficient extension services etc. Integrated aquaculture practices were at the preliminary stage in the study areas. Therefore, the socio-economic conditions of the farmers can be uplifted by adopting improved farming systems ...
Asian Journal of Medical and Biological Research, 2018
The present study was conducted to investigate effects of stocking density on growth performances... more The present study was conducted to investigate effects of stocking density on growth performances of gold fish (Carassius auratus) in hapas. Experiment was conducted for a month with three treatments where three stocking densities were T1 (10 fry/hapa), T2 (15 fry/hapa) andT3 (20 fry/hapa) each having three replications which were selected randomly. In the present experiment hapa (3ft × 2ft × 2ft) with 1 mm mesh net was used. Gold fish fry having a mean body weight of 0.007 g were used in all treatments. Fishes were fed at the rate of 10% of their body weight containing 34.11% protein. Water quality parameters were monitored at 10 days interval and the ranges were –temperature 24.75 to 27.75 oC, dissolved oxygen 3.68 to 4.09 mg/L, pH 7.3 to 8.16, ammonia 0.3 to 1 mg/L, nitrite 0.01 to 0.03 mg/L, phosphate 0.6 to 1 mg/L and alkalinity 119 to 187 mg/L. At the growth performances were evaluated by comparing mean final body weight, specific growth rate and food conversion ratio. The pre...
2009 IEEE International Conference on Communications, 2009
Among the schemes, proposed in the literature to solve the route optimization problem in NEtwork ... more Among the schemes, proposed in the literature to solve the route optimization problem in NEtwork MObility (NEMO), the prefix delegation-based schemes perform better than other schemes. Depending on the way the prefix are delegated, the prefix delegation-based schemes result in difference in performance under different speed at various distance from the home network (network to which mobile network usually belongs). Therefore, there is a need to evaluate the performance of individual prefix delegation-based scheme to find an appropriate scheme based on speed and distance from home network. In this paper, we identify the differences of the prefix delegation-based schemes using simulation. Results reveal that performance of the schemes depends on speed of the network and distance from home network.
Saratoga is a protocol for fast file transfers across dedicated links in private networks, using ... more Saratoga is a protocol for fast file transfers across dedicated links in private networks, using small amounts of feedback for loss recovery. It is in use to download large amounts of imaging data from remote-sensing satellites, where the link environment is highly asymmetric and uplinks are constrained. However, Saratoga lacks a rate-control mechanism to allow fair share with co-existing flows for simultaneous competing transfers, or for across the congested Internet where it must coexist fairly with TCP. TFRC, a selfand TCP-Friendly Rate Control mechanism, can be adopted for Saratoga and leverage its existing protocol information. Use of TFRC normally requires significant changes in protocol operation, including additional data in feedback. We design a sender-based TFRC for Saratoga, needing only simple modifications within the sender and using only existing feedback information. This sender-based TFRC is shown to share the bottleneck-bandwidth fairly under various network conditions, allowing Saratoga to be adapted for shared links or for the congested Internet, while still supporting the asymmetric environments that Saratoga was originally developed for.
MILCOM 2008 - 2008 IEEE Military Communications Conference, 2008
NEtwork MObility (NEMO) protocols can be used to manage aggregate mobility of multiple IP-enabled... more NEtwork MObility (NEMO) protocols can be used to manage aggregate mobility of multiple IP-enabled devices onboard a Low Earth Orbit satellite (a mobile network on-board). NEMO protocols enjoy several performance advantages, such as reduced signaling, increased manageability and conservation of satellite link bandwidth as compared to host mobility protocols for individual devices. In addition, NEMO protocols can provide continuous connectivity at upper layers using nested NEMO (a mobile network attached to another) during unavailability of ground stations where as connection would terminate if host mobility protocols were used. Therefore, NEMO protocols needs to be evaluated in space. We propose an architecture for NEMO in space, where the devices are connected together using an onboard Local Area Network. The architecture includes nesting where a mobile network on-board a satellite can attach to another. We evaluated NEMO protocols for the architecture using a space friendly data transfer protocol called Saratoga because widely used protocols like TCP is not space friendly. Simulation based performance evaluation shows continuity of connections at upper layers and performance superiority of Saratoga to TCP for NEMO in space.
A number of prefix delegation-based schemes have been proposed in the literature to solve the rou... more A number of prefix delegation-based schemes have been proposed in the literature to solve the route optimization problem in NEMO, where a group of hosts move together as a mobile network. The route optimization solutions generate different amounts of overheads that depend on the characteristics of the mobile network and mobility parameters. The overheads limit performance, giving rise to the need to carry out a comparative performance evaluation of the schemes to aid in the selection of a scheme; currently there is no tool which can aid in the selection. The objective of this paper is to develop analytical models to allow comparison among the schemes, and selection of an appropriate scheme for a given mobility scenario and mobile network characteristics. Results show that a single scheme does not suit all mobility scenarios and network characteristics. Selection of a scheme should, therefore, consider adaptation to the scenario and characteristics. The schemes could also be extended to dynamically adapt to changing scenario and characteristics.
Network Mobility (NEMO) is coined for the efficient mobility management of multiple nodes which a... more Network Mobility (NEMO) is coined for the efficient mobility management of multiple nodes which are moving together as a mobile network. A major limitation of the basic protocol in NEMO is the inefficient route for communication. A number of prefix delegation-based schemes have been proposed in the literature to solve the route optimization problem in NEMO. Approaches used by the schemes trade off delivery of packets through the partially-optimized route with signaling and other processing overheads. Cost of delivering packets through the partially-optimized route along with signaling and other processing cost need to be measured to find out the gain from tradeoff. However, cost analysis performed so far on NEMO protocols consider only the cost of signaling. In this paper, we have developed analytical framework to measure the costs of the basic protocol for NEMO, and four representative prefix delegation-based schemes. Our results show that cost of packet delivery through the partially-optimized route dominates over other costs. Therefore, optimizing the route completely is preferable to reduction of signaling as far as cost of network mobility is concerned. Our framework will help in visualizing the effects of future network expansion on the cost of route optimization schemes of NEMO.
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