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Showing papers by "Hong Kong University of Science and Technology published in 2010"


Journal ArticleDOI
TL;DR: The relationship between transfer learning and other related machine learning techniques such as domain adaptation, multitask learning and sample selection bias, as well as covariate shift are discussed.
Abstract: A major assumption in many machine learning and data mining algorithms is that the training and future data must be in the same feature space and have the same distribution. However, in many real-world applications, this assumption may not hold. For example, we sometimes have a classification task in one domain of interest, but we only have sufficient training data in another domain of interest, where the latter data may be in a different feature space or follow a different data distribution. In such cases, knowledge transfer, if done successfully, would greatly improve the performance of learning by avoiding much expensive data-labeling efforts. In recent years, transfer learning has emerged as a new learning framework to address this problem. This survey focuses on categorizing and reviewing the current progress on transfer learning for classification, regression, and clustering problems. In this survey, we discuss the relationship between transfer learning and other related machine learning techniques such as domain adaptation, multitask learning and sample selection bias, as well as covariate shift. We also explore some potential future issues in transfer learning research.

18,616 citations


Journal ArticleDOI
TL;DR: In this paper, a review of the current understanding of carbon nanotubes and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT-based functionalization on the properties of polymers.
Abstract: Carbon nanotubes (CNTs) hold the promise of delivering exceptional mechanical properties and multi-functional characteristics. Ever-increasing interest in applying CNTs in many different fields has led to continued efforts to develop dispersion and functionalization techniques. To employ CNTs as effective reinforcement in polymer nanocomposites, proper dispersion and appropriate interfacial adhesion between the CNTs and polymer matrix have to be guaranteed. This paper reviews the current understanding of CNTs and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT dispersion and functionalization on the properties of CNT/polymer nanocomposites. The fabrication techniques and potential applications of CNT/polymer nanocomposites are also highlighted.

2,849 citations


Journal ArticleDOI
Thomas J. Hudson1, Thomas J. Hudson2, Warwick Anderson3, Axel Aretz4  +270 moreInstitutions (92)
15 Apr 2010
TL;DR: Systematic studies of more than 25,000 cancer genomes will reveal the repertoire of oncogenic mutations, uncover traces of the mutagenic influences, define clinically relevant subtypes for prognosis and therapeutic management, and enable the development of new cancer therapies.
Abstract: The International Cancer Genome Consortium (ICGC) was launched to coordinate large-scale cancer genome studies in tumours from 50 different cancer types and/or subtypes that are of clinical and societal importance across the globe. Systematic studies of more than 25,000 cancer genomes at the genomic, epigenomic and transcriptomic levels will reveal the repertoire of oncogenic mutations, uncover traces of the mutagenic influences, define clinically relevant subtypes for prognosis and therapeutic management, and enable the development of new cancer therapies.

2,041 citations


Journal ArticleDOI
TL;DR: This article examined how product and consumer characteristics moderate the influence of online consumer reviews on product sales using data from the video game industry and found that online reviews are more influential for less popular games and games whose players have greater Internet experience.
Abstract: This article examines how product and consumer characteristics moderate the influence of online consumer reviews on product sales using data from the video game industry. The findings indicate that online reviews are more influential for less popular games and games whose players have greater Internet experience. The article shows differential impact of consumer reviews across products in the same product category and suggests that firms' online marketing strategies should be contingent on product and consumer characteristics. The authors discuss the implications of these results in light of the increased share of niche products in recent years.

1,952 citations


Journal ArticleDOI
TL;DR: The potential of transformation optics to create functionalities in which the optical properties can be designed almost at will is reviewed, which can be used to engineer various optical illusion effects, such as the invisibility cloak.
Abstract: Transformation optics describes the capability to design the path of light waves almost at will through the use of metamaterials that control effective materials properties on a subwavelength scale. In this review, the physics and applications of transformation optics are discussed.

1,085 citations


Journal ArticleDOI
TL;DR: In this article, the authors examine how cultural differences influence the returns of momentum strategies and find that individualism is positively associated with trading volume and volatility, as well as with the magnitude of momentum profits, and that momentum profits are also positively related to analyst forecast dispersion, transaction costs, and the familiarity of the market to foreigners.
Abstract: This paper examines how cultural differences influence the returns of momentum strategies. Cross-country cultural differences are measured with an individualism index developed by Hofstede (2001), which is related to overconfidence and self-attribution bias. We find that individualism is positively associated with trading volume and volatility, as well as to the magnitude of momentum profits. Momentum profits are also positively related to analyst forecast dispersion, transaction costs, and the familiarity of the market to foreigners, and negatively related to firm size and volatility. However, the addition of these and other variables does not dampen the relation between individualism and momentum profits.

830 citations


Journal ArticleDOI
TL;DR: A win‐win strategy would be the elimination of the ACQ effect without sacrificing other functional properties of the luminophores, in the work reported here, which has developed a new approach.
Abstract: The development of efficient luminescent materials in the solid state is of both scientific and technological interest. An obstacle to their development is the notorious aggregation-caused quenching (ACQ) effect: the emission of conventional luminophores is often weakened in the solid state in comparison to in solution, due to aggregate formation in the condensed phase. [1‐3] The ACQ problem must be properly tackled, because the luminophores are commonly used as solid films in their practical applications. Various chemical, physical, and engineering approaches have been taken to frustrate luminophore aggregation. [4,5] The attachment of bulky alicyclics, encapsulation by amphiphilic surfactants, and blending with transparent polymers are widely used methods to impede aggregate formation. These processes, however, are often accompanied by severe side effects. The steric effects of bulky alicyclics, for example, can twist the conformations of the chromophoric units and jeopardize the electronic conjugation in the luminophores, and the electronic effects of the saturated surfactants and nonconjugated polymers can dilute the luminophore density and obstruct the charge transport in electroluminescence (EL) devices. The current approaches to the problem are thus far from ideal, because the ACQ effect is alleviated at the expense of other useful properties of the luminophores. A win‐win strategy would be the elimination of the ACQ effect without sacrificing other functional properties of the luminophores. In the work reported here, we have developed such a new approach. Triphenylamine (TPA) and its derivatives are luminescent when dissolved in good solvents [6] for them but become less emissive when aggregated in the solid state, and are therefore typical ACQ luminophores. [7] For

794 citations


Journal ArticleDOI
TL;DR: Recent progress in the development of AIE-based bio/chemosensors for assays of nuclease and AChE activities, screening of inhibitors, and detection of various analytes including charged biopolymers, ionic species, volatile and explosive organic compounds is summarized.
Abstract: New fluorescent sensors have been developed, utilizing the aggregation-induced emission (AIE) attribute of silole and tetraphenylethene luminogens. In this feature article, we briefly summarize recent progress in the development of AIE-based bio/chemosensors for assays of nuclease and AChE activities, screening of inhibitors, and detection of various analytes including charged biopolymers, ionic species, volatile and explosive organic compounds.

785 citations


Journal ArticleDOI
TL;DR: The authors linked CEO hubris to firm risk taking and examined the moderating role of managerial discretion in this relationship, drawing on upper echelons theory and behavioral decision theory, they examined the role of discretion in the relationship.
Abstract: This study linked CEO hubris to firm risk taking and examined the moderating role of managerial discretion in this relationship. Drawing on upper echelons theory and behavioral decision theory, we ...

780 citations


Proceedings ArticleDOI
26 Apr 2010
TL;DR: This work develops a general solution to sentiment classification when the authors do not have any labels in a target domain but have some labeled data in a different domain, regarded as source domain and proposes a spectral feature alignment (SFA) algorithm to align domain-specific words from different domains into unified clusters, with the help of domain-independent words as a bridge.
Abstract: Sentiment classification aims to automatically predict sentiment polarity (e.g., positive or negative) of users publishing sentiment data (e.g., reviews, blogs). Although traditional classification algorithms can be used to train sentiment classifiers from manually labeled text data, the labeling work can be time-consuming and expensive. Meanwhile, users often use some different words when they express sentiment in different domains. If we directly apply a classifier trained in one domain to other domains, the performance will be very low due to the differences between these domains. In this work, we develop a general solution to sentiment classification when we do not have any labels in a target domain but have some labeled data in a different domain, regarded as source domain. In this cross-domain sentiment classification setting, to bridge the gap between the domains, we propose a spectral feature alignment (SFA) algorithm to align domain-specific words from different domains into unified clusters, with the help of domain-independent words as a bridge. In this way, the clusters can be used to reduce the gap between domain-specific words of the two domains, which can be used to train sentiment classifiers in the target domain accurately. Compared to previous approaches, SFA can discover a robust representation for cross-domain data by fully exploiting the relationship between the domain-specific and domain-independent words via simultaneously co-clustering them in a common latent space. We perform extensive experiments on two real world datasets, and demonstrate that SFA significantly outperforms previous approaches to cross-domain sentiment classification.

778 citations


Journal ArticleDOI
TL;DR: The full workflow of the TPP is described, along with an example on a sample data set, demonstrating that the setup and use of the tools are straightforward and well supported and do not require specialized informatic resources or knowledge.
Abstract: The Trans-Proteomic Pipeline (TPP) is a suite of software tools for the analysis of MS/MS data sets. The tools encompass most of the steps in a proteomic data analysis workflow in a single, integrated software system. Specifically, the TPP supports all steps from spectrometer output file conversion to protein-level statistical validation, including quantification by stable isotope ratios. We describe here the full workflow of the TPP and the tools therein, along with an example on a sample data set, demonstrating that the setup and use of the tools are straightforward and well supported and do not require specialized informatic resources or knowledge.

Proceedings ArticleDOI
26 Apr 2010
TL;DR: This paper shows that, by using the location data based on GPS and users' comments at various locations, it can discover interesting locations and possible activities that can be performed there for recommendations and extensively evaluated the system.
Abstract: With the increasing popularity of location-based services, such as tour guide and location-based social network, we now have accumulated many location data on the Web. In this paper, we show that, by using the location data based on GPS and users' comments at various locations, we can discover interesting locations and possible activities that can be performed there for recommendations. Our research is highlighted in the following location-related queries in our daily life: 1) if we want to do something such as sightseeing or food-hunting in a large city such as Beijing, where should we go? 2) If we have already visited some places such as the Bird's Nest building in Beijing's Olympic park, what else can we do there? By using our system, for the first question, we can recommend her to visit a list of interesting locations such as Tiananmen Square, Bird's Nest, etc. For the second question, if the user visits Bird's Nest, we can recommend her to not only do sightseeing but also to experience its outdoor exercise facilities or try some nice food nearby. To achieve this goal, we first model the users' location and activity histories that we take as input. We then mine knowledge, such as the location features and activity-activity correlations from the geographical databases and the Web, to gather additional inputs. Finally, we apply a collective matrix factorization method to mine interesting locations and activities, and use them to recommend to the users where they can visit if they want to perform some specific activities and what they can do if they visit some specific places. We empirically evaluated our system using a large GPS dataset collected by 162 users over a period of 2.5 years in the real-world. We extensively evaluated our system and showed that our system can outperform several state-of-the-art baselines.

Journal Article
01 Jan 2010-Physics
TL;DR: The experimental realization and theoretical understanding of a membrane-type acoustic metamaterial with very simple construct, capable of breaking the mass density law of sound attenuation in the 100-1000 Hz regime by a significant margin are presented.
Abstract: We present the experimental realization and theoretical explanation of a membrane-type acoustic metamaterial of very simple structure,capable of breaking the mass density law of sound attenuation in the 100—1000Hz regime by a significant margin(~200 times).Due to the membrane's weak elastic moduli,low frequency oscillation patterns can be found even in a small elastic film with fixed boundaries defined by a rigid grid.The vibrational eigenfrequencies can be tuned by placing a small mass at the center of the membrane sample.Near-total reflection is achieved at a frequency in between two eigenmodes where the in-plane average of the normal displacement is zero.By using finite element simulations,a negative dynamic mass is explicitly demonstrated at frequencies around the total reflection frequency.Excellent agreement between theory and experiment is obtained.We also show that the present mechanism can explain the phenomenon of total microwave transmission through subwavelength slits in metallic fractals,at frequencies intermediate between two local resonances.

Journal ArticleDOI
TL;DR: In this paper, the authors reported efficient phosphorescence from the crystals of benzophenone and its derivatives with a general formula of (X-C6H4)2C═O (X = F, Cl, Br) as well as methyl 4-bromobenzoate and 4,4′-dibromobiphenyl under ambient conditions.
Abstract: Phosphorescence has rarely been observed in pure organic chromophore systems at room temperature. We herein report efficient phosphorescence from the crystals of benzophenone and its derivatives with a general formula of (X-C6H4)2C═O (X = F, Cl, Br) as well as methyl 4-bromobenzoate and 4,4′-dibromobiphenyl under ambient conditions. These luminogens are all nonemissive when they are dissolved in good solvents, adsorbed on TLC plates, and doped into polymer films, because active intramolecular motions such as rotations and vibrations under these conditions effectively annihilate their triplet excitons via nonradiative relaxation channels. In the crystalline state, the intramolecular motions are restricted by the crystal lattices and intermolecular interactions, particularly C−H···O, N−H···O, C−H···X (X = F, Cl, Br), C−Br···Br−C, and C−H···π hydrogen bonding. The physical constraints and multiple intermolecular interactions collectively lock the conformations of the luminogen molecules. This structural rigi...

Journal ArticleDOI
TL;DR: Conditions under which strong duality holds and efficient algorithms for the optimal beamforming problem are given and rank reduction procedures to achieve a lower rank solution are proposed.
Abstract: Consider a downlink communication system where multiantenna base stations transmit independent data streams to decentralized single-antenna users over a common frequency band. The goal of the base stations is to jointly adjust the beamforming vectors to minimize the transmission powers while ensuring the signal-to-interference-noise ratio requirement of each user within the system. At the same time, it may be necessary to keep the interference generated on other coexisting systems under a certain tolerable level. In addition, one may want to include general individual shaping constraints on the beamforming vectors. This beamforming problem is a separable homogeneous quadratically constrained quadratic program, and it is difficult to solve in general. In this paper, we give conditions under which strong duality holds and propose efficient algorithms for the optimal beamforming problem. First, we study rank-constrained solutions of general separable semidefinite programs (SDPs) and propose rank reduction procedures to achieve a lower rank solution. Then we show that the SDP relaxation of three classes of optimal beamforming problem always has a rank-one solution, which can be obtained by invoking the rank reduction procedures.

Journal ArticleDOI
TL;DR: In this article, the authors examined the change in foreign mutual fund investment in firms that began using International Financial Reporting Standards (IFRS) after its mandatory adoption in the European Union (EU) in 2005.
Abstract: Proponents of International Financial Reporting Standards (IFRS) argue that mandating a uniform set of accounting standards improves financial statement comparability that in turn attracts greater cross-border investment. Our study tests this assertion by examining the change in foreign mutual fund investment in firms that began using IFRS after its mandatory adoption in the European Union (EU) in 2005. We hypothesize that firms experience larger increases in foreign mutual fund ownership when there is a credible increase in uniformity from IFRS adoption. We define a credible increase in uniformity as a large increase in the number of industry peers using the same accounting standards in countries where IFRS is credibly implemented. Consistent with our hypothesis, we find that subsequent to mandatory IFRS adoption, the increase in foreign mutual fund investment is greater among the firms that experience relatively large increases in uniformity and are in countries with strong implementation credibility.

Journal ArticleDOI
TL;DR: In this paper, an analytical closed-form expression of an achievable secrecy rate was derived for the case of noncolluding eavesdroppers and an upper bound on the secrecy rate is provided.
Abstract: We consider the problem of secure communication with multiantenna transmission in fading channels. The transmitter simultaneously transmits an information-bearing signal to the intended receiver and artificial noise to the eavesdroppers. We obtain an analytical closed-form expression of an achievable secrecy rate and use it as the objective function to optimize the transmit power allocation between the information signal and the artificial noise. Our analytical and numerical results show that equal power allocation is a simple yet near-optimal strategy for the case of noncolluding eavesdroppers. When the number of colluding eavesdroppers increases, more power should be used to generate the artificial noise. We also provide an upper bound on the SNR, above which, the achievable secrecy rate is positive and shows that the bound is tight at low SNR. Furthermore, we consider the impact of imperfect channel state information (CSI) at both the transmitter and the receiver and find that it is wise to create more artificial noise to confuse the eavesdroppers than to increase the signal strength for the intended receiver if the CSI is not accurately obtained.

Journal ArticleDOI
01 May 2010-Carbon
TL;DR: In this paper, the surface, interfacial and dispersion properties of carbon nanotubes (CNTs), and the mechanical properties of the CNT/epoxy composites affected by CNT functionalization are investigated.

BookDOI
01 Dec 2010
TL;DR: In this article, the importance of Electrode Material in the Electrochemical Treatment of Wastewater Containing Organic Pollutants for Wastewater Treatment has been discussed, including the use of both anode and cathode reactions in wastewater treatment.
Abstract: Basic Principles of the Electrochemical Mineralization of Organic Pollutants for Wastewater Treatment.- Importance of Electrode Material in the Electrochemical Treatment of Wastewater Containing Organic Pollutants.- Techniques of Electrode Fabrication.- Modeling of Electrochemical Process for the Treatment of Wastewater Containing Organic Pollutants.- Green Electroorganic Synthesis Using BDD Electrodes.- Domestic and Industrial Water Disinfection Using Boron-Doped Diamond Electrodes.- Drinking Water Disinfection by In-line Electrolysis: Product and Inorganic By-Product Formation.- Case Studies in the Electrochemical Treatment of Wastewater Containing Organic Pollutants Using BDD.- The Persulfate Process for the Mediated Oxidation of Organic Pollutants.- Electrocoagulation in Water Treatment.- Electroflotation.- Electroreduction of Halogenated Organic Compounds.- Principles and Applications of Solid Polymer Electrolyte Reactors for Electrochemical Hydrodehalogenation of Organic Pollutants.- Preparation, Analysis and Behaviors of Ti-Based SnO2 Electrode and the Function of Rare-Earth Doping in Aqueous Wastes Treatment.- Wet Electrolytic Oxidation of Organics and Application for Sludge Treatment.- Environmental Photo(electro)catalysis: Fundamental Principles and Applied Catalysts.- Solar Disinfection of Water by TiO2 Photoassisted Processes: Physicochemical, Biological, and Engineering Aspects.- Fabrication of Photoelectrode Materials.- Use of Both Anode and Cathode Reactions in Wastewater Treatment.

Journal ArticleDOI
TL;DR: BOOST has identified some disease-associated interactions between genes in the major histocompatibility complex region in the type 1 diabetes data set and can serve as a computationally and statistically useful tool in the coming era of large-scale interaction mapping in genome-wide case-control studies.
Abstract: Gene-gene interactions have long been recognized to be fundamentally important for understanding genetic causes of complex disease traits. At present, identifying gene-gene interactions from genome-wide case-control studies is computationally and methodologically challenging. In this paper, we introduce a simple but powerful method, named "BOolean Operation-based Screening and Testing" (BOOST). For the discovery of unknown gene-gene interactions that underlie complex diseases, BOOST allows examination of all pairwise interactions in genome-wide case-control studies in a remarkably fast manner. We have carried out interaction analyses on seven data sets from the Wellcome Trust Case Control Consortium (WTCCC). Each analysis took less than 60 hr to completely evaluate all pairs of roughly 360,000 SNPs on a standard 3.0 GHz desktop with 4G memory running the Windows XP system. The interaction patterns identified from the type 1 diabetes data set display significant difference from those identified from the rheumatoid arthritis data set, although both data sets share a very similar hit region in the WTCCC report. BOOST has also identified some disease-associated interactions between genes in the major histocompatibility complex region in the type 1 diabetes data set. We believe that our method can serve as a computationally and statistically useful tool in the coming era of large-scale interaction mapping in genome-wide case-control studies.

Posted Content
TL;DR: An analytical closed-form expression of an achievable secrecy rate is obtained and used as the objective function to optimize the transmit power allocation between the information signal and the artificial noise and shows that the bound is tight at low SNR.
Abstract: We consider the problem of secure communication with multi-antenna transmission in fading channels. The transmitter simultaneously transmits an information bearing signal to the intended receiver and artificial noise to the eavesdroppers. We obtain an analytical closed-form expression of an achievable secrecy rate, and use it as the objective function to optimize the transmit power allocation between the information signal and the artificial noise. Our analytical and numerical results show that equal power allocation is a simple yet near optimal strategy for the case of non-colluding eavesdroppers. When the number of colluding eavesdroppers increases, more power should be used to generate the artificial noise. We also provide an upper bound on the signal-to-noise ratio (SNR) above which the achievable secrecy rate is positive and show that the bound is tight at low SNR. Furthermore, we consider the impact of imperfect channel state information (CSI) at both the transmitter and the receiver and find that it is wise to create more artificial noise to confuse the eavesdroppers than to increase the signal strength for the intended receiver if the CSI is not accurately obtained.

Journal ArticleDOI
TL;DR: The structure, systemic transformation and bioavailability of ginsenosides are reviewed before illustration on how these molecules exert their functions via interactions with steroidal receptors are illustrated.
Abstract: The therapeutic potential of ginseng has been studied extensively, and ginsenosides, the active components of ginseng, are shown to be involved in modulating multiple physiological activities. This article will review the structure, systemic transformation and bioavailability of ginsenosides before illustration on how these molecules exert their functions via interactions with steroidal receptors. The multiple biological actions make ginsenosides as important resources for developing new modalities. Yet, low bioavailability of ginsenoside is one of the major hurdles needs to be overcome to advance its use in clinical settings.

Posted Content
TL;DR: In this paper, a simple but powerful method, named "BOolean Operation based Screening and Testing" (BOOST), is introduced to discover unknown gene-gene interactions that underlie complex diseases.
Abstract: Gene-gene interactions have long been recognized to be fundamentally important to understand genetic causes of complex disease traits. At present, identifying gene-gene interactions from genome-wide case-control studies is computationally and methodologically challenging. In this paper, we introduce a simple but powerful method, named `BOolean Operation based Screening and Testing'(BOOST). To discover unknown gene-gene interactions that underlie complex diseases, BOOST allows examining all pairwise interactions in genome-wide case-control studies in a remarkably fast manner. We have carried out interaction analyses on seven data sets from the Wellcome Trust Case Control Consortium (WTCCC). Each analysis took less than 60 hours on a standard 3.0 GHz desktop with 4G memory running Windows XP system. The interaction patterns identified from the type 1 diabetes data set display significant difference from those identified from the rheumatoid arthritis data set, while both data sets share a very similar hit region in the WTCCC report. BOOST has also identified many undiscovered interactions between genes in the major histocompatibility complex (MHC) region in the type 1 diabetes data set. In the coming era of large-scale interaction mapping in genome-wide case-control studies, our method can serve as a computationally and statistically useful tool.

Journal ArticleDOI
TL;DR: A critical review of the expatriate adjustment literature that focuses on studies that have considered other stakeholders in addition to expatriates themselves is presented in this paper, where the most important, implicit assumptions that scholars seem to have made and that may have restricted the theoretical and empirical advancement of the literature are delineated.

Journal ArticleDOI
TL;DR: In this article, a carbon-supported PdNi catalysts for the ethanol oxidation reaction in alkaline direct ethanol fuel cells are successfully synthesized by the simultaneous reduction method using NaBH4 as reductant.

Journal ArticleDOI
TL;DR: In this article, the authors examined the impact of key supplier and customer integration processes (i.e., information sharing and product codevelopment with suppliers and customer, respectively) on product innovation as well as their impact on product performance.

Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate that smooth and flat surfaces combining hydrophilic and hydrophobic patterns improve pool boiling performance, up to a 65% and 100% increase in critical heat flux and heat transfer coefficients.
Abstract: We demonstrate that smooth and flat surfaces combining hydrophilic and hydrophobic patterns improve pool boiling performance. Compared to a hydrophilic surface with 7° wetting angle, the measured critical heat flux and heat transfer coefficients of the enhanced surfaces are, up to respectively, 65% and 100% higher. Different networks combining hydrophilic and hydrophobic regions are characterized. While all tested networks enhance the heat transfer coefficient, large enhancements of critical heat flux are typically found for hydrophilic networks featuring hydrophobic islands. Hydrophilic networks indeed are shown to prevent the formation of an insulating vapor layer. © 2010 American Institute of Physics. doi:10.1063/1.3485057 Boiling is an efficient process to transfer large amounts of heat at a prescribed temperature because of the large latent heat of vaporization. The term flow boiling describes the boiling of liquids forced to move along hot surfaces, while in pool boiling, the topic handled in this paper, the liquid is stagnant and in contact with a hot solid surface. 1 Besides the common experience of boiling water in an electric kettle, pool boiling has applications in metallurgy, high performance heat exchangers, and immersion cooling of electronics. Pool boiling performance is measured with two parameters, the heat transfer coefficient HTC and the critical heat flux CHF. The CHF is measured by increasing the surface temperature until a transition from high HTC to very low HTC occurs. This signifies the formation of a vapor film insulating the liquid from the heated surface, a phenomenon called dry out. Several characteristics determine the performance of a boiling surface. Nucleation sites in appropriate number and dimensions need to be provided such as cavities, rough areas, or hydrophobic islands. 2 As of today, the performance of boiling surfaces has been increased by using wicking structures to prevent dry out, 3 by increasing the surface area with fins or fluidized bed, 3‐6 and by enhancing the wettability of the surface. 5‐10 The latter strategy is justified by experiments of Wang and Dhir, 11 showing that the CHF was

Journal ArticleDOI
TL;DR: A novel set-based PSO (S-PSO) method for the solutions of some combinatorial optimization problems (COPs) in discrete space is presented and tested on two famous COPs: the traveling salesman problem and the multidimensional knapsack problem.
Abstract: Particle swarm optimization (PSO) is predominately used to find solutions for continuous optimization problems. As the operators of PSO are originally designed in an n-dimensional continuous space, the advancement of using PSO to find solutions in a discrete space is at a slow pace. In this paper, a novel set-based PSO (S-PSO) method for the solutions of some combinatorial optimization problems (COPs) in discrete space is presented. The proposed S-PSO features the following characteristics. First, it is based on using a set-based representation scheme that enables S-PSO to characterize the discrete search space of COPs. Second, the candidate solution and velocity are defined as a crisp set, and a set with possibilities, respectively. All arithmetic operators in the velocity and position updating rules used in the original PSO are replaced by the operators and procedures defined on crisp sets, and sets with possibilities in S-PSO. The S-PSO method can thus follow a similar structure to the original PSO for searching in a discrete space. Based on the proposed S-PSO method, most of the existing PSO variants, such as the global version PSO, the local version PSO with different topologies, and the comprehensive learning PSO (CLPSO), can be extended to their corresponding discrete versions. These discrete PSO versions based on S-PSO are tested on two famous COPs: the traveling salesman problem and the multidimensional knapsack problem. Experimental results show that the discrete version of the CLPSO algorithm based on S-PSO is promising.

Journal ArticleDOI
TL;DR: A CO(2) assay scheme over a wide concentration range is reported, utilizing a fluorogen with an aggregation-induced emission feature and a liquid with tunable polarity and viscosity, which indicates the process is specific, quantitative, and interferent tolerant.
Abstract: CO2 sensing is of great societal implications, as CO2 is a component of gas mixtures from many natural and anthropogenic processes with huge impacts on globe climate and human well-being. Herein we report a CO2 assay scheme over a wide concentration range, utilizing a fluorogen with an aggregation-induced emission feature and a liquid with tunable polarity and viscosity. The CO2 sensing process is specific, quantitative, and interferent tolerant.

Proceedings Article
11 Jul 2010
TL;DR: This paper discovers the principle coordinates of both users and items in the auxiliary data matrices, and transfers them to the target domain in order to reduce the effect of data sparsity.
Abstract: Data sparsity is a major problem for collaborative filtering (CF) techniques in recommender systems, especially for new users and items. We observe that, while our target data are sparse for CF systems, related and relatively dense auxiliary data may already exist in some other more mature application domains. In this paper, we address the data sparsity problem in a target domain by transferring knowledge about both users and items from auxiliary data sources. We observe that in different domains the user feedbacks are often heterogeneous such as ratings vs. clicks. Our solution is to integrate both user and item knowledge in auxiliary data sources through a principled matrix-based transfer learning framework that takes into account the data heterogeneity. In particular, we discover the principle coordinates of both users and items in the auxiliary data matrices, and transfer them to the target domain in order to reduce the effect of data sparsity. We describe our method, which is known as coordinate system transfer or CST, and demonstrate its effectiveness in alleviating the data sparsity problem in collaborative filtering. We show that our proposed method can significantly outperform several state-of-the-art solutions for this problem.