Finding optimal configurations for complex systems, such as a fleets of autonomous delivery robots, is a complex task that benefits from automation. Automated search-based approaches have been proposed to automatically find such configurations. Although the configurations found by these methods perform well on average, they may be non-stable, i.e., their performance could vary greatly across scenarios. When deploying a system with a given configuration, it is important to know that it will perform adequately for the range of possible scenarios, i.e., to reduce how much the system's performance varies between scenarios. To this end, we attempt to make the search-based approaches aware of the configurations' stability. We explore two ways of doing this: by integrating it into the fitness functions describing the target performance metrics, and by adding it as a separate set of additional objectives. We applied the two approaches to find optimal configurations of a fleet of robots for automatic delivery service. Results show that integrating the stability concern into the fitness functions is better than treating it separately.

Autonomous robots can solve different issues of delivery services, by guaranteeing less traffic congestion, less pollution, and lower operational costs. Designing such type of delivery system based on autonomous robots requires the collaboration of different stakeholders, having different concerns: the store utilising the delivery service that is interested in costs and customer satisfaction, the municipality where the service is operated that is interested in the safety of the service, and the robotic company providing the service that is interested in all previous concerns. Our industrial partner from the robotic domain is designing this type of service in a smart town, and using a simulator for assessing different configurations providing different levels of performance. Since manually designing the configurations is time consuming for engineers, in this paper, we propose a search-based approach (All) that is able to explore the space of service configurations and find the optimal ones that show the tradeoff existing among the different concerns, so that stakeholders can make an informed decision. Since assessing one configuration requires to simulate the service multiple times over different types of customer requests, the approach suffers from scalability issues. Therefore, we propose two improvements of the approach that reduce the number of required simulations (IncrSim), and the duration of the simulation (IncrTime). Ex-periments on different settings show that IncrSim and IncrTime can find results as good as those of All in less time, and better than versions of All executed for the same budget.

Autonomous robots have recently been employed for goods delivery, with the goal of reducing traffic congestion, pollution, and operational costs. The design of such a delivery service requires to select the number of robots, their operating hours, and speed. Requirements from different stakeholders must be considered: customer satisfaction, cost, and safety. To assist with said design, our industry partner Panasonic is employing a search-based approach that tries to find service configurations that optimise the three requirements, on average, across different possible sets of customer requests. The obtained Pareto fronts of solutions show the trade-off existing among the different requirements. Such Pareto fronts, albeit very useful, do not always facilitate an informed decision for the stakeholders, for they provide too many solutions (some of them very similar to each other). To tackle this issue, in this paper we propose two approaches to prune and simplify Pareto fronts. Our approaches consider the standard deviation of objective values across the different sets of customer requests; the intuition is that, if two solutions (expressed in terms of average objective values) overlap based on their standard deviations, they can be considered similar. Based on this intuition, the two pruning approaches group similar solutions and select only one representative for each partition. We assessed these pruning methods on the Pareto fronts obtained with the search-based approach employed by Panasonic. We found that they can significantly reduce the size of the Pareto fronts while retaining a reasonable amount of their unpruned quality (measured in terms of Hypervolume).

In this paper we present a testbed for the functional and performance verification and validation of product level overlay multicast (or ALM in short) applications which is a complex task due to humongous test patterns. Structured, systematic and simplified test environment is vital for product level quality validation. The key features of this testbed are network emulation, automated test scenario execution, log collection and testbed/real environment interconnectivity. The testbed uses StarBED as its mother testbed and netem as the network emulator. The key contributions of this work are calibration of netem in term of network emulation and establishing an architecture to use netem and StarBED for ALM system verification. The calibration of netem was carried out up to 30 pipes (logical links) and the results show the network emulation can be done at maximum 1.2% packet loss. One of the simple ALM verification experiments executed on the testbed took only 43 hours for execution completion compared to human execution which would take 15 weeks.

Application layer multicast (ALM) is an alternative to overcome many problems that prevent IP multicast from widely using. However, when the overlay route changes, it takes time for end-hosts to update new routing table. In this paper, we propose Treemap a technique to alleviate this problem. The main contribution of Treemap is to perform application layer routing which is self contained in a packet. As a result, end-hosts do not need to update new overlay route, yielding fast route adaptation when the overlay route changes. Furthermore, the Treemap technique can be used to extend Xcast6 (Explicit Multi-unicast for IPv6). Xcast6 Treemap sends data in network layer multicast with the support of Xcast router, otherwise it works like ALM. With nominal packet header processing, Xcast6 Treemap is well suited for loss/time sensitive applications such as video conference.

SAMTK: scalable adaptive multicast toolkit is a toolkit to bridge the gap between network researchers and application developers in the field of multi-point communication. SAMTK includes a Qt based GUI that ensures a single source multi-platform use (Linux, FreeBSD, Windows and MacOS). It provides interfaces for network plugins used by one-to-many network sockets and a simple application programming interface for application developers to develop multi-point communication applications quite easily. ALR: application layer router is a router which parses UDP packets and does a lookup in its internal forwarding table to duplicate and deliver the packets to multiple destinations. It provides NAT traversal function by using a singe UDP port both for session registration and packet delivery. The demo shows the feasibility of NAT free 3D video conferencing using application layer router and the ease of development of video conferencing applications using SAMTK.

In this paper we propose bandwidth fair N-Tree algorithm for ALM distribution tree construction and a new protocol for ALM packet replication and distribution, namely Almcast. Both the tree construction algorithm and packet replication/distribution protocol were implemented as proof-of concept by modifying an existing multi-party video conference application. The results show that N-tree algorithm takes less than 3 ms to construct ALM distribution tree for 12 nodes. Almcast implementation enables the intermediate relay node to lookup for next destination, replicate and forward packets as fast as its receiving rate at application layer.

This paper reports the design and implementation of a multicast transport-layer protocol called Sender Initiated Congestion Control (SICC) which provides adaptive flow control for multicast methods such as Application Layer Multicast (ALM) or eXplicit multi-unicast (XCAST). SICC is a NAK based protocol and is designed to be extensible to adapt to various codecs, able to handle variable length of application data units (ADU) and to notify availability of ADU at the receiver for real-time streaming. We have implemented SICC in both user space on NetBSD and kernel space on Linux 2.6.10, and have used these implementations to evaluate TCP fairness. The results show the fairly shared bandwidth with 128 competing TCP flows with 1ms timer accuracy in various RTT. We also verified the applicability to small appliance by implementing SICC/XCAST6 on a prototype network camera and evaluated SICC in a field experiment.

We demonstrate the prototype of the network camera with a multicast transport-layer protocol called Sender Initiated Congestion Control (SICC) which provides adaptive flow control for multicast methods such as Application Layer Multicast (ALM) or eXplicit multi-unicast6 (XCAST6). SICC is capable of achieving fast congestion avoidance and significantly increases throughput at receivers while still remaining TCP friendly. We verified the applicability to small appliance by implementing SICC/XCAST6 on a prototype network camera We demonstrate the prototype of network camera and receiver terminals with viewer. It shows the capability of adaptive flow control to multiple receivers with or without competing traffics.