Collaborative Financial Infrastructure Protection: Tools, Abstractions, and Middleware, Jan 10, 2012
We introduce Agilis—a lightweight collaborative event processing platform that can be deployed in... more We introduce Agilis—a lightweight collaborative event processing platform that can be deployed in a Semantic Room to facilitate sharing and correlating event data generated in real time by multiple widely distributed sources. Agilis aims to balance simplicity of use and robustness on the one hand, and scalable performance in large-scale settings on the other. To this end, Agilis is built upon the open source Hadoop's MapReduce infrastructure augmented with a RAM-based data store and several locality-oriented optimizations to ...
This paper studies the problem of maintaining eventual consistent group membership without any sy... more This paper studies the problem of maintaining eventual consistent group membership without any synchrony assumption inside an unbounded group G of processes that varies over the time (processes may join and leave the group). Eventual consistency means that if at any time all group membership changes cease, processes will converge in a flnite time to a single consistent view. Due
In this paper we study the difficulty of counting nodes in a synchronous dynamic network where no... more In this paper we study the difficulty of counting nodes in a synchronous dynamic network where nodes share the same identifier, they communicate by using a broadcast with unlimited bandwidth and, at each synchronous round, network topology may change. To count in such setting, it has been shown that the presence of a leader is necessary. We focus on a particularly interesting subset of dynamic networks, namely \textit{Persistent Distance} - ${\cal G}($PD$)_{h}$, in which each node has a fixed distance from the leader across rounds and such distance is at most $h$. In these networks the dynamic diameter $D$ is at most $2h$. We prove the number of rounds for counting in ${\cal G}($PD$)_{2}$ is at least logarithmic with respect to the network size $|V|$. Thanks to this result, we show that counting on any dynamic anonymous network with $D$ constant w.r.t. $|V|$ takes at least $D+ \Omega(\text{log}\, |V| )$ rounds where $\Omega(\text{log}\, |V|)$ represents the additional cost to be pay...
Current approaches to the development of cooperative informationsrmati arebas7 onsh710)1 to be o#... more Current approaches to the development of cooperative informationsrmati arebas7 onsh710)1 to be o#ered by cooperating organizations and on the opportunity of building coordinators and brokers on top of sh h s79((jhq The quality of data exchanged and provided by di#erents7X)P(h hampers ss h approaches as data of low quality can snh0j all over the cooperatives7)(9X At the seh time, improvement can bebas) on comparing data, correcting them anddis(j7jhq9j9 high quality data. Inthis paper, as((Q9hq90701 framework for managing data quality in cooperative informationsnform is presr ted. AnXML-bash model for data and quality datais prop osph and thedes9( of a broker, whichsQ)P0X the bes available data from di#erent s9P09Phq is pres9 ted. Sucha brokerals ss orts the improvement of data bash on feedbacks toshQ(Q shQ(Q9Qh 1
munication path between each pair of mobile hosts is formed infinitely often in an infinite run o... more munication path between each pair of mobile hosts is formed infinitely often in an infinite run of the system. A logical communication path connecting two hosts hi and hj consists of a finite sequence of phisical communication paths c,... ck (with k _ 1) established at different times t,... tk with (ti As a consequence a phisical communication path is a particular logical communication path with k equal to 1. We call such a model logically connected ad-hoc network. A logically connected ad-hoc network is composed by a set of hosts {h, h2,... h). Due to the mobility of hosts, the system can be partitioned. A partition is a non-empty subset of hosts H C_ such that for each pair of hosts (hi, hi) in H, there exists a physical communication path. As a consequence each host hi is associated to a partition Hj that contains at least hi. In a logically connected ad-hoc network, the routing protocol alone cannot always route a message between any two hosts; if they belong to distinct partit
y not prone to the partitioning phenomenon. However, there are cases where this assumption is too... more y not prone to the partitioning phenomenon. However, there are cases where this assumption is too strong, since it excludes the partitioning of the network. In this investigation we weaken the former system model by assuming that a logical communication path between each pair of mobile hosts is formed innitely often in an innite run of the system. A logical communication path connecting two hosts h i and h j consists of a nite sequence of phisical communication paths c 1 ; : : : c k (with k 1) established at dierent times t 1 ; : : : t k with (t i t i+1 ). As a consequence a phisical communication path is a particular logical communication path with k equal to 1. We call such a model logically connected ad-hoc network. A logical
Let consider a set of anonymous moving objects to be tracked in a binary sensor network. This art... more Let consider a set of anonymous moving objects to be tracked in a binary sensor network. This article studies the problem of associating deterministically a track revealed by the sensor network with the trajectory of an unique anonymous object, namely the multiple object tracking and identification (MOTI) problem. In our model, the network is represented by a sparse connected graph where each vertex represents a binary sensor and there is an edge between two sensors if an object can pass from one sensed region to another one without activating any other sensor. The difficulty of MOTI lies in the fact that the trajectories of two or more objects can be so close that the corresponding tracks on the sensor network can no longer be distinguished (track merging), thus confusing the deterministic association between an object trajectory and a track. The article presents several results. We first show that MOTI cannot be solved on a general graph of ideal binary sensors even by an omniscie...
Wiley Encyclopedia of Computer Science and Engineering, 2007
... If checkpoints are taken independently, it is possible that cascading rollback propagation, w... more ... If checkpoints are taken independently, it is possible that cascading rollback propagation, which is required to elim-inate all orphan messages, may occur ... 15. J. Tsai, An efficient index-based checkpointing protocol with constant-size control information on messages, IEEE Trans ...
Fourth IEEE International Symposium on Object-Oriented Real-Time Distributed Computing. ISORC 2001, 2001
Even though introduced for solving the consensus problem in asynchronous distributed systems, the... more Even though introduced for solving the consensus problem in asynchronous distributed systems, the notion of unreliable failure detector can be used as a powerful tool for any distributed protocol in order to get better performance by allowing the usage of aggressive time-outs to detect failures of entities executing the protocol. We present the design of a Failure Detection Service (FDS)
Proceedings 1st International Conference on Algorithms and Architectures for Parallel Processing, 1995
Abstract This paper studies properties of messages communication modes in distributed systems. It... more Abstract This paper studies properties of messages communication modes in distributed systems. It establishes a simple, hierarchical and homogeneous characterization of logically instantaneous, causally ordered and first-in-first-out communications. It is shown that a distributed computation obeys one of the previous communication modes iff a communication graph of messages does not include a cycle. This characterization plays a key role when one is interested in designing, analyzing, testing or debugging ...
Proceedings of the Fourth IEEE International Symposium on High Performance Distributed Computing, 1995
Abstract Multimedia real-time collaborative applications or groupware real-time applications requ... more Abstract Multimedia real-time collaborative applications or groupware real-time applications require participants to exchange real-time audio and video information over a communication network. This flow of information must preserve the causal dependency even though part of the information can be lost or can be discarded if it violates the tinting constraints imposed by a real-time interaction. In this paper we propose a communication abstraction to cope with unreliable communication networks with real-time delivery ...
2012 IEEE 11th International Conference on Trust, Security and Privacy in Computing and Communications, 2012
ABSTRACT We propose an efficient software architecture for private collaborative event processing... more ABSTRACT We propose an efficient software architecture for private collaborative event processing, enabling information sharing and processing among administratively and geographically disjoint organizations over the Internet. The architecture is capable of aggregating and correlating events coming from the organizations in near real-time, while preserving the privacy of sensitive data items even in the case of coalition of attackers. Although there is a rich literature in the field of secure multiparty computation techniques that preserve the privacy in a distributed systems, the ability of such systems to scale up horizontally (number of participants) and vertically (dataset per participant) is still limited. The key novelty of the architecture is the usage of a pseudo-random oracle functionality distributed among the organizations participating to the system for obfuscating the data, that allows for achieving a good level of privacy while guaranteing scalability in both dimensions. Some preliminary performance results are provided.
Collaborative Financial Infrastructure Protection: Tools, Abstractions, and Middleware, Jan 10, 2012
We introduce Agilis—a lightweight collaborative event processing platform that can be deployed in... more We introduce Agilis—a lightweight collaborative event processing platform that can be deployed in a Semantic Room to facilitate sharing and correlating event data generated in real time by multiple widely distributed sources. Agilis aims to balance simplicity of use and robustness on the one hand, and scalable performance in large-scale settings on the other. To this end, Agilis is built upon the open source Hadoop's MapReduce infrastructure augmented with a RAM-based data store and several locality-oriented optimizations to ...
This paper studies the problem of maintaining eventual consistent group membership without any sy... more This paper studies the problem of maintaining eventual consistent group membership without any synchrony assumption inside an unbounded group G of processes that varies over the time (processes may join and leave the group). Eventual consistency means that if at any time all group membership changes cease, processes will converge in a flnite time to a single consistent view. Due
In this paper we study the difficulty of counting nodes in a synchronous dynamic network where no... more In this paper we study the difficulty of counting nodes in a synchronous dynamic network where nodes share the same identifier, they communicate by using a broadcast with unlimited bandwidth and, at each synchronous round, network topology may change. To count in such setting, it has been shown that the presence of a leader is necessary. We focus on a particularly interesting subset of dynamic networks, namely \textit{Persistent Distance} - ${\cal G}($PD$)_{h}$, in which each node has a fixed distance from the leader across rounds and such distance is at most $h$. In these networks the dynamic diameter $D$ is at most $2h$. We prove the number of rounds for counting in ${\cal G}($PD$)_{2}$ is at least logarithmic with respect to the network size $|V|$. Thanks to this result, we show that counting on any dynamic anonymous network with $D$ constant w.r.t. $|V|$ takes at least $D+ \Omega(\text{log}\, |V| )$ rounds where $\Omega(\text{log}\, |V|)$ represents the additional cost to be pay...
Current approaches to the development of cooperative informationsrmati arebas7 onsh710)1 to be o#... more Current approaches to the development of cooperative informationsrmati arebas7 onsh710)1 to be o#ered by cooperating organizations and on the opportunity of building coordinators and brokers on top of sh h s79((jhq The quality of data exchanged and provided by di#erents7X)P(h hampers ss h approaches as data of low quality can snh0j all over the cooperatives7)(9X At the seh time, improvement can bebas) on comparing data, correcting them anddis(j7jhq9j9 high quality data. Inthis paper, as((Q9hq90701 framework for managing data quality in cooperative informationsnform is presr ted. AnXML-bash model for data and quality datais prop osph and thedes9( of a broker, whichsQ)P0X the bes available data from di#erent s9P09Phq is pres9 ted. Sucha brokerals ss orts the improvement of data bash on feedbacks toshQ(Q shQ(Q9Qh 1
munication path between each pair of mobile hosts is formed infinitely often in an infinite run o... more munication path between each pair of mobile hosts is formed infinitely often in an infinite run of the system. A logical communication path connecting two hosts hi and hj consists of a finite sequence of phisical communication paths c,... ck (with k _ 1) established at different times t,... tk with (ti As a consequence a phisical communication path is a particular logical communication path with k equal to 1. We call such a model logically connected ad-hoc network. A logically connected ad-hoc network is composed by a set of hosts {h, h2,... h). Due to the mobility of hosts, the system can be partitioned. A partition is a non-empty subset of hosts H C_ such that for each pair of hosts (hi, hi) in H, there exists a physical communication path. As a consequence each host hi is associated to a partition Hj that contains at least hi. In a logically connected ad-hoc network, the routing protocol alone cannot always route a message between any two hosts; if they belong to distinct partit
y not prone to the partitioning phenomenon. However, there are cases where this assumption is too... more y not prone to the partitioning phenomenon. However, there are cases where this assumption is too strong, since it excludes the partitioning of the network. In this investigation we weaken the former system model by assuming that a logical communication path between each pair of mobile hosts is formed innitely often in an innite run of the system. A logical communication path connecting two hosts h i and h j consists of a nite sequence of phisical communication paths c 1 ; : : : c k (with k 1) established at dierent times t 1 ; : : : t k with (t i t i+1 ). As a consequence a phisical communication path is a particular logical communication path with k equal to 1. We call such a model logically connected ad-hoc network. A logical
Let consider a set of anonymous moving objects to be tracked in a binary sensor network. This art... more Let consider a set of anonymous moving objects to be tracked in a binary sensor network. This article studies the problem of associating deterministically a track revealed by the sensor network with the trajectory of an unique anonymous object, namely the multiple object tracking and identification (MOTI) problem. In our model, the network is represented by a sparse connected graph where each vertex represents a binary sensor and there is an edge between two sensors if an object can pass from one sensed region to another one without activating any other sensor. The difficulty of MOTI lies in the fact that the trajectories of two or more objects can be so close that the corresponding tracks on the sensor network can no longer be distinguished (track merging), thus confusing the deterministic association between an object trajectory and a track. The article presents several results. We first show that MOTI cannot be solved on a general graph of ideal binary sensors even by an omniscie...
Wiley Encyclopedia of Computer Science and Engineering, 2007
... If checkpoints are taken independently, it is possible that cascading rollback propagation, w... more ... If checkpoints are taken independently, it is possible that cascading rollback propagation, which is required to elim-inate all orphan messages, may occur ... 15. J. Tsai, An efficient index-based checkpointing protocol with constant-size control information on messages, IEEE Trans ...
Fourth IEEE International Symposium on Object-Oriented Real-Time Distributed Computing. ISORC 2001, 2001
Even though introduced for solving the consensus problem in asynchronous distributed systems, the... more Even though introduced for solving the consensus problem in asynchronous distributed systems, the notion of unreliable failure detector can be used as a powerful tool for any distributed protocol in order to get better performance by allowing the usage of aggressive time-outs to detect failures of entities executing the protocol. We present the design of a Failure Detection Service (FDS)
Proceedings 1st International Conference on Algorithms and Architectures for Parallel Processing, 1995
Abstract This paper studies properties of messages communication modes in distributed systems. It... more Abstract This paper studies properties of messages communication modes in distributed systems. It establishes a simple, hierarchical and homogeneous characterization of logically instantaneous, causally ordered and first-in-first-out communications. It is shown that a distributed computation obeys one of the previous communication modes iff a communication graph of messages does not include a cycle. This characterization plays a key role when one is interested in designing, analyzing, testing or debugging ...
Proceedings of the Fourth IEEE International Symposium on High Performance Distributed Computing, 1995
Abstract Multimedia real-time collaborative applications or groupware real-time applications requ... more Abstract Multimedia real-time collaborative applications or groupware real-time applications require participants to exchange real-time audio and video information over a communication network. This flow of information must preserve the causal dependency even though part of the information can be lost or can be discarded if it violates the tinting constraints imposed by a real-time interaction. In this paper we propose a communication abstraction to cope with unreliable communication networks with real-time delivery ...
2012 IEEE 11th International Conference on Trust, Security and Privacy in Computing and Communications, 2012
ABSTRACT We propose an efficient software architecture for private collaborative event processing... more ABSTRACT We propose an efficient software architecture for private collaborative event processing, enabling information sharing and processing among administratively and geographically disjoint organizations over the Internet. The architecture is capable of aggregating and correlating events coming from the organizations in near real-time, while preserving the privacy of sensitive data items even in the case of coalition of attackers. Although there is a rich literature in the field of secure multiparty computation techniques that preserve the privacy in a distributed systems, the ability of such systems to scale up horizontally (number of participants) and vertically (dataset per participant) is still limited. The key novelty of the architecture is the usage of a pseudo-random oracle functionality distributed among the organizations participating to the system for obfuscating the data, that allows for achieving a good level of privacy while guaranteing scalability in both dimensions. Some preliminary performance results are provided.
Uploads
Papers by Roberto Baldoni