Technology
Deep Multimodal Hashing with Orthogonal Regularization
Wang, Daixin (Tsinghua University) | Cui, Peng (Tsinghua University) | Ou, Mingdong (Tsinghua University) | Zhu, Wenwu (Tsinghua University)
Hashing is an important method for performing efficient similarity search. With the explosive growth of multimodal data, how to learn hashing-based compact representations for multimodal data becomes highly non-trivial. Compared with shallow structured models, deep models present superiority in capturing multimodal correlations due to their high nonlinearity. However, in order to make the learned representation more accurate and compact, how to reduce the redundant information lying in the multimodal representations and incorporate different complexities of different modalities in the deep models is still an open problem. In this paper, we propose a novel deep multimodal hashing method, namely Deep Multimodal Hashing with Orthogonal Regularization (DMHOR), which fully exploits intra-modality and inter-modality correlations. In particular, to reduce redundant information, we impose orthogonal regularizer on the weighting matrices of the model, and theoretically prove that the learned representation is guaranteed to be approximately orthogonal. Moreover, we find that a better representation can be attained with different numbers of layers for different modalities, due to their different complexities. Comprehensive experiments on WIKI and NUS-WIDE, demonstrate a substantial gain of DMHOR compared with state-of-the-art methods.
Building Hierarchies of Concepts via Crowdsourcing
Sun, Yuyin (University of Washington) | Singla, Adish (ETH Zurich) | Fox, Dieter (University of Washington) | Krause, Andreas (ETH Zurich)
Hierarchies of concepts are useful in many applications from navigation to organization of objects. Usually, a hierarchy is created in a centralized manner by employing a group of domain experts, a time-consuming and expensive process. The experts often design one single hierarchy to best explain the semantic relationships among the concepts, and ignore the natural uncertainty that may exist in the process. In this paper, we propose a crowdsourcing system to build a hierarchy and furthermore capture the underlying uncertainty. Our system maintains a distribution over possible hierarchies and actively selects questions to ask using an information gain criterion. We evaluate our methodology on simulated data and on a set of real world application domains. Experimental results show that our system is robust to noise, efficient in picking questions, cost-effective, and builds high quality hierarchies.
Strategic Abstention Based on Preference Extensions: Positive Results and Computer-Generated Impossibilities
Brandl, Florian (Technische Universitรคt Mรผnchen) | Brandt, Felix (Technische Universitรคt Mรผnchen) | Geist, Christian (Technische Universitรคt Mรผnchen) | Hofbauer, Johannes (Technische Universitรคt Mรผnchen)
Voting rules are powerful tools that allow multiple agents to aggregate their preferences in order to reach joint decisions. A common flaw of some voting rules, known as the no-show paradox, is that agents may obtain a more preferred outcome by abstaining from an election. We study strategic abstention for set-valued voting rules based on Kelly's and Fishburn's preference extensions. Our contribution is twofold. First, we show that, whenever there are at least five alternatives, every Pareto-optimal majoritarian voting rule suffers from the no-show paradox with respect to Fishburn's extension. This is achieved by reducing the statement to a finite---yet very large---problem, which is encoded as a formula in propositional logic and then shown to be unsatisfiable by a SAT solver. We also provide a human-readable proof which we extracted from a minimal unsatisfiable core of the formula. Secondly, we prove that every voting rule that satisfies two natural conditions cannot be manipulated by strategic abstention with respect to Kelly's extension. We conclude by giving examples of well-known Pareto-optimal majoritarian voting rules that meet these requirements.
Computing Horn Rewritings of Description Logics Ontologies
Kaminski, Mark (University of Oxford) | Grau, Bernardo Cuenca (University of Oxford)
We study the problem of rewriting an ontology O1 expressed in a DL L1 into an ontology O2 in a Horn DL L2 such that O1 and O2 are equisatisfiable when extended with an arbitrary dataset. ย Ontologies that admit such rewritings are amenable to reasoning techniques ensuring tractability in data complexity. ย After showing undecidability whenever L1 extends ALCF , we focus on devising efficiently checkable conditions that ensure existence of a Horn rewriting. ย By lifting existing techniques for rewriting Disjunctive Datalog programs into plain Datalog to the case of arbitrary first-order programs with function symbols, we identify a class of ontologies that admit Horn rewritings of polynomial size. ย Our experiments indicate that many real-world ontologies satisfy our sufficient conditions and thus admit polynomial Horn rewritings.
A Space Alignment Method for Cold-Start TV Show Recommendations
Chang, Shiyu (University of Illinois at Urbana-Champaign) | Zhou, Jiayu (Samsung Research America) | Chubak, Pirooz (Samsung Research America) | Hu, Junling (Samsung Research America) | Huang, Thomas (University of Illinois at Urbana-Champaign)
In recent years, recommendation algorithms have become one of the most active research areas driven by the enormous industrial demands. Most of the existing recommender systems focus on topics such as movie, music, e-commerce etc., which essentially differ from the TV show recommendations due to the cold-start and temporal dynamics. Both effectiveness (effectively handling the cold-start TV shows) and efficiency (efficiently updating the model to reflect the temporal data changes) concerns have to be addressed to design real-world TV show recommendation algorithms. In this paper, we introduce a novel hybrid recommendation algorithm incorporating both collaborative user-item relationship as well as item content features. The cold-start TV shows can be correctly recommended to desired users via a so called space alignment technique. On the other hand, an online updating scheme is developed to utilize new user watching behaviors. We present experimental results on a real TV watch behavior data set to demonstrate the significant performance improvement over other state-of-the-art algorithms.
Spectrum-Based Fault Localisation for Multi-Agent Systems
Passos, Lรบcio S. (University of Porto) | Abreu, Rui (University of Porto) | Rossetti, Rosaldo J. F. (University of Porto)
However, generation of MAS models that SFL is a well-suited technique for MASs. is both error-prone and time intense, as it exponentially Literature has shown that there is no standard similarity increases with the number of agents coefficient that yields the best result for SFL [Yoo et al., 2014; and their interactions. In this paper, we propose Hofer et al., 2015; Le et al., 2013]. Empirical evaluation is a lightweight, automatic debugging-based technique, therefore essential to establish which set of heuristics excels coined ESFL-MAS, which shortens the diagnostic for the specific context to which SFL is being applied. To the process, while only relying on minimal best of our knowledge, SFL has not as yet been applied to information about the system. ESFL-MAS uses a diagnose behavioural faults in MASs; there is hence the need heuristic that quantifies the suspiciousness of an to empirically evaluate different formulae using known faults agent to be faulty; therefore, different heuristics to compare the performance yielded by several coefficients.
Mixed Discrete-Continuous Heuristic Generative Planning Based on Flow Tubes
Fernandez-Gonzalez, Enrique (Massachusetts Institute of Technology) | Karpas, Erez (Massachusetts Institute of Technology) | Williams, Brian C. (Massachusetts Institute of Technology)
Nowadays, robots are programmed with a mix of discrete and continuous low level behaviors by experts in a very time consuming and expensive process. Existing automated planning approaches are either based on hybrid model predictive control techniques, which do not scale well due to time discretization, or temporal planners, which sacrifice plan expressivity by only supporting discretized fixed rates of change in continuous effects. We introduce Scotty, a mixed discrete-continuous generative planner that finds the middle ground between these two. Scotty can reason with linear time evolving effects whose behaviors can be modified by bounded control variables, with no discretization involved. Our planner exploits the expressivity of flow tubes, which compactly encapsulate continuous effects, and the performance of heuristic forward search. The generated solution plans are better suited for robust execution, as executives can use the flexibility in both time and continuous control variables to react to disturbances.
Modeling Quantum Entanglements in Quantum Language Models
Xie, Mengjiao (Tianjin University) | Hou, Yuexian (Tianjin University) | Zhang, Peng (Tianjin University) | Li, Jingfei (Tianjin University) | Li, Wenjie (The Hong Kong Polytechnic University) | Song, Dawei (Tianjin University)
Recently, a Quantum Language Model (QLM) was proposed to model term dependencies upon Quantum Theory (QT) framework and successively applied in Information Retrieval (IR). Nevertheless, QLM's dependency is based on co-occurrences of terms and has not yet taken into account the Quantum Entanglement (QE), which is a key quantum concept and has a significant cognitive implication. In QT, an entangled state can provide a more complete description for the nature of realities, and determine intrinsic correlations of considered objects globally, rather than those co-occurrences on the surface. It is, however, a real challenge to decide and measure QE using the classical statistics of texts in a post-measurement configuration. In order to circumvent this problem, we theoretically prove the connection between QE and statistically Unconditional Pure Dependence (UPD). Since UPD has an implementable deciding algorithm, we can in turn characterize QE by extracting the UPD patterns from texts. This leads to a measurable QE, based on which we further advance the existing QLM framework. We empirically compare our model with related models, and the results demonstrate the effectiveness of our model.
Slogans Are Not Forever: Adapting Linguistic Expressions to the News
Gatti, Lorenzo (FBK-IRST) | รzbal, Gรถzde (FBK-IRST) | Guerini, Marco (Trento RISE) | Stock, Oliviero (FBK-IRST) | Strapparava, Carlo (FBK-IRST)
Artistic creation is often based on the concept of blending. Linguistic creativity is no exception, as demonstrated for instance by the importance of metaphors in poetry. Blending can also be used to evoke a secondary concept while playing with an already given piece of language, either with the intention of making the secondary concept well perceivable to the reader, or instead, to subtly evoke something additional. Current language technology can do a lot in this connection, and automated language creativity can be useful in cases where input or target are to change continuously, making human production not feasible. In this work we present a system that takes existing well-known expressions and innovates them by bringing in a novel concept coming from evolving news. The technology is composed of several steps concerned with the selection of the sortable concepts and the production of novel expressions, largely relying on state of the art corpus-based methods. Proposed applications include: i) producing catchy news headlines by "parasitically" exploiting well known successful expressions and adapting them to the news at hand; ii) generating adaptive slogans that allude to news of the day and give life to the concept evoked by the slogan; iii) providing artists with an application for boosting their creativity.
Biclustering Gene Expressions Using Factor Graphs and the Max-Sum Algorithm
Denitto, Matteo (University of Verona) | Farinelli, Alessandro (University of Verona) | Bicego, Manuele (University of Verona)
Biclustering is an intrinsically challenging and highly complex problem, particularly studied in the biology field, where the goal is to simultaneously cluster genes and samples of an expression data matrix. In this paper we present a novel approach to gene expression biclustering by providing a binary Factor Graph formulation to such problem. In more detail, we reformulate biclustering as a sequential search for single biclusters and use an efficient optimization procedure based on the Max Sum algorithm. Such approach, drastically alleviates the scaling issues of previous approaches for biclustering based on Factor Graphs obtaining significantly more accurate results on synthetic datasets. A further analysis on two real-world datasets confirms the potentials of the proposed methodology when compared to alternative state of the art methods.