Citywide Inclusive Sanitation Guidance Note: What Is Citywide Inclusive Sanitation and Why Is It Needed?

This guidance note explains how the concept of citywide inclusive sanitation (CWIS) for developing more comprehensive, effective, and sustainable sanitation services in urban areas. CWIS focuses on providing urban areas with access to and benefits from adequate and sustainable sanitation services, including the safe, effective, and sustainable management of all human waste along the whole sanitation service chain. This guidance note is part of a series that aims to share essential knowledge to embed CWIS principles in planning and delivering sanitation services to ADB developing member countries. These learning materials were prepared by ADB’s Water Sector Group and structured along the ADB project processing cycle.

Designing two-period decentralized service chain incentives with the consideration of customer acquisition and retention

PurposeThe authors address a two-dimensional (both customer acquisition and retention) incentive in a decentralized service chain consisting of a risk-neutral brand and agent (or averse). Design/methodology/approachThe authors focus on the relationship between acquisition and retention, that is, retained customers (repeated purchases) are based on and come from the acquired (new) customers in the former period. The authors also design a two-period separate incentive on both dimensions.FindingsThe authors found that a targeted incentive strategy should be applied for achieving more revenue when the incentive intensities are relatively small. Otherwise, the brand needs to adjust the targeted incentive strategy into incentivizing the opposite dimension, particularly on acquisition. Under the optimal contract, the brand needs to be very careful with deciding the fixed part of the incentive salary and the incentive intensities on both dimensions. For example, the fixed salary initially decreases and then increases in the incentive intensities. For the optimal incentive policies, the brand should incentivize acquisition but outsource retention if the agent is risk-neutral. When the agent is becoming risk-averse, the brand should lower its incentive intensity as the risk degree and variances become larger. Interestingly, the brand may benefit from introducing risks.Originality/valueThe study contributes to the literature by considering the following points. First, the authors extend the principal-agent incentive model by considering two-period decisions of customer acquisition and retention. Second, based on the two-period principal-agent problem, the authors design separate incentive intensities on acquisition and retention, respectively. While, most of the literature focused on acquisition incentives. Third, different from other works focusing on either risk-neutral or risk-averse environments, the authors consider both and compare the cases of risk-neutral and risk-averse to analyze the impact of risk on the optimal decisions and the brand's expected profit.

Deep Reinforcement Learning-Based Algorithm for VNF-SC Deployment

Network function virtualization (NFV) has the potential to lead to significant reductions in capital expenditure and can improve the flexibility of the network. Virtual network function (VNF) deployment problem will be one of key problems that need to be addressed in NFV. To solve the problem of routing and VNF deployment, an optimization model, which minimizes the maximum index of used frequency slots, the number of used frequency slots, and the number of initialized VNF, is established. In this optimization model, the dependency among the different VNFs is considered. In order to solve the service chain mapping problem of high dynamic virtual network, a new virtual network function service chain mapping algorithm PDQN-VNFSC was proposed by combining prediction algorithm and DQN (Deep Q-Network). Firstly, the real-time mapping of virtual network service chains is modeled into a partial observable Markov decision process. Then, the real-time mapping process of virtual network service chain is optimized by using global and long-term benefits. Finally, the service chain of virtual network function is mapped through the learning decision framework of offline learning and online deployment. The simulation results show that, compared with the existing algorithms, the proposed algorithm has a lower the maximum index of used frequency slots, the number of used frequency slots, and the number of initialized VNF.

Managing Non-Sewered Sanitation for Achieving Sustainable Development Goal 6 in India

The challenge of ensuring clean water and safely managed sanitation towards meeting the Sustainable Development Goal 6 is made more complex by unplanned urbanisation in South Asia. Nearly 50% of all toilet-owning households globally and 83% in South Asia depend on non-networked sanitation, with a multi-step service chain comprising containment, collection, conveyance, and treatment of faecal waste. Over the last few years, South Asian governments have begun to eschew the long-enduring preference for centralised sewerage infrastructure in favour of better management of non-networked sanitation as part of city-level wastewater management systems. However, these interventions have largely excluded the household-level containment systems that hold the potential to create both adverse localised and diffuse public health and environmental outcomes if dysfunctional. The present Chapter discusses evidence from a multi-state household survey in India to assess the nature and quality of containment systems in use by urban Indian households. Secondly, it reviews approaches to their governance under more evolved paradigms to inform an ecosystem-wide strategy for managing these systems in India and countries with similar contexts.

HS-MOEA/D: An Oriented Algorithm for Delay and Reliability VNF-SC Deployment

Network function virtualization (NFV) technology can realize on-demand distribution of network resources and improve network flexibility. It has become one of the key technologies for next-generation communications. Virtual network function service chain (VNF-SC) deployment is an important problem faced by network function virtualization technology. In this paper, the problem, VNF deployment for VNF-SC, is investigated. First, a two-objective mathematical model, which maximizes balancing and reliability of SFC, is established. In this model, VNFs are divided into two classes, i.e., part of required VNFs in each VNF-SC is dependent, others are independent. Second, harmony search-based MOEA/D (HS-MOEA/D) is proposed to solve the model effectively. In HS-MOEA/D, Chebyshev decomposition mechanism is used to transform multiobjective optimization problem into a series of single-objective optimization subproblems. A new evolutionary strategy is deeply studied in order to propose a new harmony search (HS) algorithm. Finally, to show high performance of the proposed algorithm, a large number of experiments are conducted. The simulation results show that the proposed algorithm enhances the reliability of SFC and reduces the end-to-end delay.