A secure and lightweight ad-hoc routing algorithm for personal networks

Over the past few years, there has been increasing interest in utilizing Personal Area Networks (PANs) to offer users innovative and personalized services. This interest is a consequence of the widespread use of mobile devices such as laptops, mobile phones, PDAs, digital cameras, wireless headsets, etc. to carry out a variety of user-centric tasks. The PAN itself is built upon an ad-hoc network where devices trust their neighbors to route their packets. The cooperative nature of ad-hoc networks allows malicious nodes to easily cripple the network by inserting false route information, replaying old messages, modifying messages of other nodes, etc. An applicable area still under research, and the focus of this paper, is secure routing protocols for ad-hoc networks. To achieve availability in the PAN, the routing protocol used must be robust against both dynamically changing topology and malicious attacks. However, the heterogeneous nature of Personal Network (PN) devices means that traditional security mechanisms are too resource intensive to be sufficient by themselves. This paper describes a new ad-hoc secure routing protocol for Personal Networks (PNs), suitable in a limited multi-hop scenario. This protocol is based on ADOV and relies on efficient cryptographic primitives to safeguard the security and privacy of PN users. Following that, a number of attacks in the area of ad-hoc networks are discussed, and it is shown that the new algorithm protects against multiple un-coordinated active attackers, in spite of compromised nodes in the network

Participatory Irrigation Management and its Financial Viability: A Case Study

Water is a key input of agriculture. In the past, the area under cultivation was small and there was less stress on farmers to grow more and more of each crop. Water was considered a free good. The situation has changed since. The increase in cropping intensity has led to a rise in the demand for irrigation water. Water is not a free good any more. The provision of irrigation water to the farmer’s fields is going to be costlier. The Government of Pakistan is spending heavily on the operation and maintenance of the irrigation system yet shortage of funds is a major reason for deferred maintenance, which threatens the operational integrity of the irrigation system [World Bank (1988) and Haq (1995)]. The shortfall in O&M funding was estimated to be more than 24 percent in 1993 [World Bank (1994)]. As poor O&M has direct effect on the productivity of agriculture, indirectly it affects the whole economy [Carruthers (1981)]. The allocation of funds for the increasing O&M costs is becoming a problem for the Government of Pakistan with every successive year. One logical answer to this problem is to increase abiana1 fees from the users of irrigation water supplies. The revenue collected through abiana may be used for O&M purposes, but it has been reported that the revenue collection is far less than the expenditures incurred. Resultantly the gap has been increasing every year [Chaudhry (1989)]. This situation demands investigation of abiana recovery and increasing O&M costs to know the real situation which in turn will help in deciding whether it is feasible to divert the financing of O&M activities towards farmer organisations (completely or partially). This paper aims at estimating the present level of operation and maintenance expenditures of the H-4-R Distributary and the present situation of the abiana collection and the extent of its leakage through different means.

Net Gains from Conjunctive Use of Surface and Ground Water

Pakistan is fortunate enough because its soils, topography and climate are generally suitable for farming but its agriculture sector faces the problem of scarcity of the irrigation water. This paucity of irrigation supplies has forced the farmers to use the ground water to augment their surface supplies. The quality of ground water in Pakistan varies from fit for irrigation to moderately saline to sodic. Thus the tubewell owners in the marginal quality ground water areas are bound to use the tubewell water in conjunction with the surface water on their farms. Currently the farmers are using about 65.75 BCM of ground water in Pakistan [Halcrow (2002)]. The international literature is filled with the studies on conjunctive water management and its impact on crop productivity and related issues [Gangwar and Toorn (1987); Bredehoeft and Young (1983); Gorelick (1988); Lingen (1988); O’Mara (1988); Shah (1988); Brewer and Sharma (2000); Datta and Dayal (2000); Raju and Brewer (2000); Sakhtivadivel and Chawala (2002) and Chaudhary and Shah (2003)]. In Pakistan, the review of literature shows that all of the previous studies conducted in the arena of water management reported the management problems leading to the inefficiencies in irrigation application and reduction in crop productivity, [Kijne and Velde (1991); Mustafa (1991) and Siddiq (1994)]. Few of the studies took into consideration the impact of waterlogging and salinity on productivity at farm level [Meyer, et al. (1996); Prathaper, et al. (1997) and O’Connell and Khan (1999)]. None of these studies have taken into consideration the trade-offs between gross farm income, ground water and salinity at irrigation subdivision level. To answer the issues of spatial differences in the trade offs between gross farm income, ground water and salinity at irrigation Subdivision level, this paper presents the results of the optimisation modeling at the Subdivisional level

Trade Liberalisation Policies, Intra-regional Trade and Opportunities for Sustainable Agricultural Development

Many of the Near East (NE) countries are currently opening their agricultural markets at three distinct but interacting levels: unilateral liberalisation, regional integration schemes and multilateral trade liberalisation. These changes hold important implications for intra- and extra-regional trade, use of agricultural resources and sustainability of agricultural development in the NE countries. Unilaterally, and since the late 1980s, most countries of the region have liberalised their agriculture sectors by eliminating or reducing input subsidies, removing or reducing guaranteed producer prices, reducing the number of subsidised commodities and liberalising the exchange rate and the trade regime. Most of the implicit and explicit subsidies for agricultural inputs and outputs were withdrawn. However, some of the NE countries were able to continue supporting agriculture mainly for food security reasons. Experiences showed that domestic reform is necessary but not sufficient condition for economic growth.

Estimating the Production Potential of Major Crops in Pakistan’s Irrigated Agriculture during the 21st Century

Land and irrigation are the basic resources in agriculture. The role and importance of these resources and their contribution towards productivity, in the context of the country’s increasing population, can hardly be exaggerated. Pakistani agriculture is set in a very distinctive situation of an increasing population on the one hand and diminishing resources on the other. The population of Pakistan was reported to be 131.63 million in 1996 and is projected to be 207 million in 2013 [Pakistan (1996) and WSIP (1990)]. The agriculture sector has to face the difficult task of doubling the existing food production by the turn of this century. The situation demands horizontal and vertical growth in the productivity, either by bringing more land under cultivation, or by increasing the cropping intensity of the existing land resources. This can also be accomplished by bringing more land under cultivation from the cultivable uncultivated area (a large proportion of which exists on medium and large farms under waterlogged or saline conditions). In this context, it becomes important to identify the nature of the relationship that exists between farm size and unculturable wastelands and the kinds of changes the green revolution/SCARPs projects introduced to this relationship.

'Poverty Reduction through Improved Agricultural Water Management: proceedings of the Workshop on Pro-poor Intervention Strategies in Irrigated Agriculture in Asia, Islamabad, Pakistan, 23-24 April 2003

Water management / Irrigated farming / Poverty / Food security / Households / Income / Drought / Forest policy / Natural disasters / Land ownership / Groundwater / Water market / Water balance / Legislation / Tubewells / Institutional development / Crop production / Wages / Economic aspects / Tillage / Water harvesting / Public policy / Surface water / Labor / Exports / Public sector

Net Gains from Conjunctive Use of Surface and Ground Water

Pakistan is fortunate enough because its soils, topography and climate are generally suitable for farming but its agriculture sector faces the problem of scarcity of the irrigation water. This paucity of irrigation supplies has forced the farmers to use the ground water to augment their surface supplies. The quality of ground water in Pakistan varies from fit for irrigation to moderately saline to sodic. Thus the tubewell owners in the marginal quality ground water areas are bound to use the tubewell water in conjunction with the surface water on their farms. Currently the farmers are using about 65.75 BCM of ground water in Pakistan [Halcrow (2002)]. The international literature is filled with the studies on conjunctive water management and its impact on crop productivity and related issues [Gangwar and Toorn (1987); Bredehoeft and Young (1983); Gorelick (1988); Lingen (1988); O’Mara (1988); Shah (1988); Brewer and Sharma (2000); Datta and Dayal (2000); Raju and Brewer (2000); Sakhtivadivel and Chawala (2002) and Chaudhary and Shah (2003)]. In Pakistan, the review of literature shows that all of the previous studies conducted in the arena of water management reported the management problems leading to the inefficiencies in irrigation application and reduction in crop productivity, [Kijne and Velde (1991); Mustafa (1991) and Siddiq (1994)]. Few of the studies took into consideration the impact of waterlogging and salinity on productivity at farm level [Meyer, et al. (1996); Prathaper, et al. (1997) and O’Connell and Khan (1999)]. None of these studies have taken into consideration the trade-offs between gross farm income, ground water and salinity at irrigation subdivision level