November 28th, 2015
Ph.D. Dissertation Defense
Computer Science and Electrical Engineering
University of Maryland, Baltimore County
Rapid Plan Adaptation Through Offline
Analysis of Potential Plan Disruptors
Robert H. Holder, III
9:00am Wednesday, 9 December 2015, ITE 325b
Computing solutions to intractable planning problems is particularly problematic in dynamic, real-time domains. For example, visitation planning problems, such as a delivery truck that must deliver packages to various locations, can be mapped to a Traveling Salesman Problem (TSP). The TSP is an NP-complete problem, requiring planners to use heuristics to find solutions to any significantly large problem instance, and can require a lengthy amount of time. Planners that solve the dynamic variant, the Dynamic Traveling Salesman Problem (DTSP), calculate an efficient route to visit a set of potentially changing locations. When a new location becomes known, DTSP planners typically use heuristics to add the new locations to the previously computed route. Depending on the placement and quantity of these new locations, the efficiency of this adapted, approximated solution can vary significantly. Solving a DTSP in real time thus requires choosing between a TSP planner, which produces a relatively good but slowly generated solution, and a DTSP planner, which produces a less optimal solution relatively quickly.
Instead of quickly generating approximate solutions or slowly generating better solutions at runtime, this dissertation introduces an alternate approach of precomputing a library of high-quality solutions prior to runtime. One could imagine a library containing a high-quality solution for every potential problem instance consisting of potential new locations, but this approach obviously does not scale with increasing problem complexity. Because complex domains preclude creating a comprehensive library, I instead choose a subset of all possible plans to include. Strategic plan selection will ensure that the library contains appropriate plans for future scenarios.
Committee: Drs. Marie desJardins (co-chair), Tim Finin (co-chair), Tim Oates, Donald Miner, R. Scott Cost
November 21st, 2015
Log files comprise a record of different events happening in various applications, operating systems and even in network devices. Originally they were used to record information for diagnostic and debugging purposes. Nowadays, logs are also used to track events which can be used in auditing and forensics in case of malicious activities or systems attacks. Various softwares like intrusion detection systems, web servers, anti-virus and anti-malware systems, firewalls and network devices generate logs with useful information, that can be used to protect against such system attacks. Analyzing log files can help in pro- actively avoiding attacks against the systems. While there are existing tools that do a good job when the format of log files is known, the challenge lies in cases where log files are from unknown devices and of unknown formats. We propose a framework that takes any log file and automatically gives out a semantic interpretation as a set of RDF Linked Data triples. The framework splits a log file into columns using regular expression-based or dictionary-based classifiers. Leveraging and modifying our existing work on inferring the semantics of tables, we identify every column from a log file and map it to concepts either from a general purpose KB like DBpedia or domain specific ontologies such as IDS. We also identify relationships between various columns in such log files. Converting large and verbose log files into such semantic representations will help in better search, integration and rich reasoning over the data.
November 20th, 2015
Introduction to Deep Learning
Zhiguang Wang and Hang Gao
10:00am Monday, 23 November 2015, ITE 346
Deep learning has been a hot topic and all over the news lately. It is introduced with the ambition of moving Machine Learning closer to Artificial Intelligence, one of its original goals. Since the introduction of the concept of deep learning, various relevant algorithms are proposed and have achieved significant success in their corresponding areas. This talk aims at providing a brief overview of most common deep learning algorithms, along with their application on different tasks.
In this talk, Steve (Zhiguang Wang) will give a brief introduction about the application of deep learning algorithms in computer vision and speech, some basic viewpoints about training methods and attacking the non-convexity in deep neural nets along with some misc about deep learning.
On the other hand, Hang Gao will talk about common application of deep learning algorithms in Natural Language Processing, covering semantic, syntactic and sentiment analysis. He will also give a discussion on the limits of current application of deep learning algorithms in NLP and provide some ideas on possible future trend.
November 8th, 2015
In this report, we describe the Unified Cyber Security ontology (UCO) to support situational awareness in cyber security systems. The ontology is an effort to incorporate and integrate heterogeneous information available from different cyber security systems and most commonly used cyber security standards for information sharing and exchange. The ontology has also been mapped to a number of existing cyber security ontologies as well as concepts in the Linked Open Data cloud. Similar to DBpedia which serves as the core for Linked Open Data cloud, we envision UCO to serve as the core for the specialized cyber security Linked Open Data cloud which would evolve and grow with the passage of time with additional cybersecurity data sets as they become available. We also present a prototype system and concrete use-cases supported by the UCO ontology. To the best of our knowledge, this is the first cyber security ontology that has been mapped to general world ontologies to support broader and diverse security use-cases. We compare the resulting ontology with previous efforts, discuss its strengths and limitations, and describe potential future work directions.
November 5th, 2015
Extracting Structured Summaries
from Text Documents
Dr. Zareen Syed
Research Assistant Professor, UMBC
10:30am, Monday, 9 November 2015, ITE 346, UMBC
In this talk, Dr. Syed will present unsupervised approaches for automatically extracting structured summaries composed of slots and fillers (attributes and values) and important facts from articles, thus effectively reducing the amount of time and effort spent on gathering intelligence by humans using traditional keyword based search approaches. The approach first extracts important concepts from text documents and links them to unique concepts in Wikitology knowledge base. It then exploits the types associated with the linked concepts to discover candidate slots and fillers. Finally it applies specialized approaches for ranking and filtering slots to select the most relevant slots to include in the structured summary.
Compared with the state of the art, Dr. Syed’s approach is unrestricted, i.e., it does not require manually crafted catalogue of slots or relations of interest that may vary over different domains. Unlike Natural Language Processing (NLP) based approaches that require well-formed sentences, the approach can be applied on semi-structured text. Furthermore, NLP based approaches for fact extraction extract lexical facts and sentences that require further processing for disambiguating and linking to unique entities and concepts in a knowledge base, whereas, in Dr. Syed’s approach, concept linking is done as a first step in the discovery process. Linking concepts to a knowledge base provides the additional advantage that the terms can be explicitly linked or mapped to semantic concepts in other ontologies and are thus available for reasoning in more sophisticated language understanding systems.
November 1st, 2015
To efficiently utilize their cloud based services, consumers have to continuously monitor and manage the Service Level Agreements (SLA) that define the service performance measures. Currently this is still a time and labor intensive process since the SLAs are primarily stored as text documents. We have significantly automated the process of extracting, managing and monitoring cloud SLAs using natural language processing techniques and Semantic Web technologies. In this paper we describe our prototype system that uses a Hadoop cluster to extract knowledge from unstructured legal text documents. For this prototype we have considered publicly available SLA/terms of service documents of various cloud providers. We use established natural language processing techniques in parallel to speed up cloud legal knowledge base creation. Our system considerably speeds up knowledge base creation and can also be used in other domains that have unstructured data.