141 research outputs found
Structurally Optimal LEGO Tiling: Complexity and Approximability of Exact Cover with Submodular Objectives
Get PDFWe introduce and analyze the \emph{Structurally Optimal LEGO Tiling} problem: given a 2D binary grid , a finite library of axis-aligned rectangular bricks, and a structural fitness function , find an exact, non-overlapping layout that covers using bricks from while maximizing . We study this problem through the lens of theoretical computer science, assuming is modular, monotone, or submodular—natural models for objectives like interlocking strength, stability, or material efficiency. Our main results establish that the decision version is NP-complete even for domino bricks and modular , yet polynomial-time solvable when contains only unit bricks. We prove that while a -approximation exists for the partial coverage relaxation under submodular , the exact cover requirement admits no constant-factor approximation unless . We further characterize the compatibility between tiling feasibility and optimization, showing it always holds for modular objectives but can fail for submodular ones. Finally, we demonstrate that the feasible layout space lacks matroid or polymatroid structure (except in trivial cases) and that natural LP relaxations suffer unbounded integrality gaps. Together, these results delineate the computational boundaries of automated, structure-aware LEGO design and illuminate fundamental trade-offs between geometric feasibility and combinatorial optimization
How packaging designs of cosmetics affect female consumers' purchasing behavior?
Get PDFThe topic of the thesis is “How packaging designs of cosmetics affect female consumers’ purchasing behavior?” Its aim is to identify whether female consumers are attracted by packaging designs of cosmetics, and how packaging designs of cosmetics affect different female consumer groups. Research question is: “If packaging of cosmetics affects which cosmetics females prefer when they buy cosmetics? And if so, is this preferences related to age and income?” To answer this question, the author uses data collection---questionnaire to investigate this topic. Limitations of the thesis concern nationalities and age groups. Due to questionnaires is distributed in Finland and Arcada University, the author find that most respondents are Finnish and young people, thus, results of minority groups may be not very accurate. The main theories are characteristics affecting consumer behavior, segmenting consumer markets, product and packaging design, and international product decisions. Results of the thesis are most female consumers think packaging design of cosmetics are important, and they will buy good-looking packaging cosmetics. Different nationalities and age groups of female consumers prefer different styles. Most consumers think that it would be best to spend the lowest cost on packaging; however, the higher monthly incomes, the greater proportion of high acceptable cost on packaging design
A nemzetközi utazás hatása a kereskedelemre
No full textThis paper uses a gravity model with export flows as the explanatory variable, country’s GDP, country’s population and distance between two countries as control variables, international arrivals as the variable of interest, and adds other explanatory variables such as the Global Peace Index and World Happiness Index, and dummy variables of Visa-free, Visa-on-arrival and common Free Trade Area, to the analysis. The author conducts a panel data analysis on bilateral exports between ASEAN countries and five trading partner countries for the period 2012-2020. The empirical results show that the coefficient on international arrivals as the variable of interest is statistically positive and significant. This implies that booming international travel positively contributes to the size of international trade between ASEAN and the five countries. Coefficients on GDP and geographical distance as control variables are both significant in the expected direction. In addition, other explanatory variables related to international travel, such as visa-free, visa-on-arrival, common free trade area and global peace index, are all statistically significant under certain conditions. Thus, promoting the recovery and development of international travel can be an effective starting point for international trade growth between ASEAN and its trading partner countries today and in the years to come. Moreover, the findings of this paper can provide a direction and recommendations for ASEAN countries to follow in the process of promoting travel integration.International Economics and BusinessMSc/M
Toward climate resilient land-use planning:Indicators for adaptation and mitigation
Get PDFAs climate and land-use pressures intensify, Climate resilient land-use (CRLU) planning is becoming increasingly essential. This study conducts a scoping review of 115 studies to examine how adaptation and mitigation are addressed in CRLU planning, focusing on the indicators used to measure these goals. The review analyzes indicators across agriculture, forestry, and urban planning sectors, revealing an imbalance emphasizing climate mitigation over adaptation indicators. It also distinguishes urban and rural contexts, highlighting the need for region-specific indicators. Synergies and trade-offs between adaptation and mitigation indicators are then discussed to inform integrated planning and avoid unintended negative consequences. The review also evaluates CRLU modeling approaches, from pattern-based to process-based, and finds that their effectiveness depends on selecting indicators closely aligned with planning objectives. A conceptual framework is finally proposed to guide the selection of targeted, context-sensitive, comprehensive indicators, supporting more effective CRLU planning.<br/
OmniNet : An Expandable Causal Inference Network for Multiple Modalities
Get PDFOpen Access via the Springer Nature agreement We would like to thank the reviewers and editors for handling our manuscript.Peer reviewe
Evaluation of conditional survival outcomes in patients with redefined anaplastic thyroid carcinoma
Get PDFObjectiveConditional survival (CS) offers a more precise assessment of prognosis by continuously updating to reflect the current state. This study aimed to analyze the CS outcome of redefined anaplastic thyroid carcinoma (rATC).MethodsA cohort comprising 1424 patients diagnosed with rATC between 2000 and 2018 was extracted from the Surveillance, Epidemiology, and End Results database and subsequently divided into training and validation sets at a ratio of 3:1. We analyzed the CS prognosis of these patients. A Lasso Cox regression model was employed to determine independent risk factors for long-term survival and to develop a predictive nomogram integrating CS analysis, aiming to provide CS estimates and stratify the risk among rATC patients.ResultsThe likelihood of achieving 5-year CS escalated from 8% after diagnosis to 44%, 68%, 82%, and 95% after 1, 2, 3, and 4 years of survival, respectively. As patients endured longer, their probability of further years of survival augmented. The Lasso Cox regression analysis identified age, tumor stage, surgery, radiotherapy and chemotherapy as the most influential prognostic factors associated with outcomes. Ultimately, we successfully established a novel CS-nomogram, aiming to provide dynamic survival updates for these patients. Our predictive model can quantify patients’ risk and stratify it accordingly. Furthermore, after evaluation, the performance of our predictive model was found to be satisfactory.ConclusionUtilizing extensive SEER datasets, we devised and validated a CS-nomogram, enabling the prediction of the conditional probability of survival for rATC patients. This facilitates the incorporation of survivorship duration into prognostic assessments
Microevolution of the mexT and lasR Reinforces the Bias of Quorum Sensing System in Laboratory Strains of Pseudomonas aeruginosa PAO1
Get PDF15 Pág.The Pseudomonas aeruginosa strain PAO1 has routinely been used as a laboratory model for quorum sensing (QS). However, the microevolution of P. aeruginosa laboratory strains resulting in genetic and phenotypic variations have caused inconsistencies in QS research. To investigate the underlying causes of these variations, we analyzed 5 Pseudomonas aeruginosa PAO1 sublines from our laboratory using a combination of phenotypic characterization, high throughput genome sequencing, and bioinformatic analysis. The major phenotypic variations among the sublines spanned across the levels of QS signals and virulence factors such as pyocyanin and elastase. Furthermore, the sublines exhibited distinct variations in motility and biofilm formation. Most of the phenotypic variations were mapped to mutations in the lasR and mexT, which are key components of the QS circuit. By introducing these mutations in the subline PAO1-E, which is devoid of such mutations, we confirmed their influence on QS, virulence, motility, and biofilm formation. The findings further highlight a possible divergent regulatory mechanism between the LasR and MexT in the P. aeruginosa. The results of our study reveal the effects of microevolution on the reproducibility of most research data from QS studies and further highlight mexT as a key component of the QS circuit of P. aeruginosa.This work was supported by the Natural Research Foundation of China (Grant No. 31330002), Key Projects of Guangzhou Science and Technology Plan (Grant No. 201804020066), Guangdong Technological Innovation Strategy of Special Funds (Grant No. 2018B020205003), and China Scholarship Council (CSC) (Grant 202008440425).Peer reviewe
Does Environmental Decentralization Promote Renewable Energy Development? A Local Government Competition Perspective
No full textRenewable energy development is a long-term means of addressing the climate challenge and achieving environmental sustainability. This study examines the relationship between environmental decentralization, local government competition, and renewable energy production using panel data from 30 Chinese provinces from 2000 to 2021. The empirical results show that environmental decentralization significantly inhibits renewable energy development, indicating a lack of foresight among local governments in environmental governance issues. In addition, local government competition amplifies the detrimental effects of environmental decentralization on renewable energy production. Although the decentralization of environmental administrative power hinders renewable energy production, the decentralization of environmental monitoring power promotes it. However, insufficient evidence is available to conclude that regional characteristics and threshold variables can alter the inhibitory effect of environmental decentralization on renewable energy production, even though the effects of environmental decentralization on the production of renewable energy exhibit geographical variation and non-linear characteristics. The findings of this study contribute to optimizing environmental policies to motivate local governments to pursue long-term environmental governance goals
Surface Feature Prediction for Laser Ablated 40Cr13 Stainless Steel Based on Extreme Learning Machine
No full textDetermining an optimal combination of laser process parameters can significantly improve the efficiency and quality of 40Cr13 steel surface processing. In this study, two machine learning models (ELMSS and ELMPS) were proposed to predict the processing results of surface features to optimize process parameters. The prediction accuracies of the proposed models were always higher than those of traditional back propagation (BP) and radial basis function (RBF) neural networks, and the calculation time of the proposed models was significantly reduced. In comparison, the prediction accuracy ranking for ablation depth was ELMSS (92.6%), BP (89.8%), and RBF (89.6%), and for the ablation width, it was ELMSS (98.3%), BP (97.4%), and RBF (96.1%). The material removal rate was 92.4%, 91.1%, and 89.1% for ELMSS, BP, and RBF, respectively. Finally, the prediction accuracy ranking for surface roughness was 86.8%, 80.7%, and 79.5% for ELMPS, BP, and RBF, respectively. After optimization by the genetic algorithm, the prediction accuracies of the proposed models for the depth, width, material removal rate, and surface roughness reached 94.0%, 99.0%, 93.2%, and 91.2%, respectively. With the support of ELMSS and ELMPS, the results of the surface features can be predicted before machining and the appropriate process parameters can be selected in advance
Resource Management for Device-to-Device Communications in Heterogeneous Networks Using Stackelberg Game
Get PDFDevice-to-device (D2D) communications and femtocell systems can bring significant benefits to users’ throughput. However, the complicated three-tier interference among macrocell, femtocell, and D2D systems is a challenging issue in heterogeneous networks. As D2D user equipment (UE) can cause interference to cellular UE, scheduling and allocation of channel resources and power of D2D communication need elaborate coordination. In this paper, we propose a joint scheduling and resource allocation scheme to improve the performance of D2D communication. We take UE rate and UE fairness into account by performing interference management. First, we construct a Stackelberg game framework in which we group a macrocellular UE, a femtocellular UE, and a D2D UE to form a two-leader one-follower pair. The cellular UE are leaders, and D2D UE is the follower who buys channel resources from the leaders. We analyze the equilibrium of the game and obtain solutions to the equilibrium. Second, we propose an algorithm for joint scheduling of D2D pairs based on their utility. Finally, we perform computer simulations to study the performance of the proposed scheme
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