Strategic effort allocation in online innovation tournaments

Online innovation tournaments, such as those hosted by crowdsourcing platforms (e.g., Kaggle), have been widely adopted by firms to evolve creative solutions to various problems. Solvers compete in these tournaments to earn rewards. In such competitive environments, it is imperative that solvers provide creative solutions with minimum effort. This article explores the factors that influence the solvers’ effort allocation decisions in a dynamic tournament setting. Specifically, comprehensive time variant data of teams that participated in crowdsourcing competitions on Kaggle were analyzed to gain insight into how solvers continually formulate strategies in light of performance feedback obtained through interim ranking. The results suggest that solvers strategically allocate their efforts throughout the contest to dynamically optimize their payoffs through balancing the probability of winning and the cost of expending effort. In particular, solvers tend to increase their efforts toward the end of tournaments or when they get closer to winning positions. Furthermore, our findings indicate that a last-minute surge in effort is more prevalent among high-skill solvers than in those with lower skill levels. In addition to providing insights that may help solvers develop strategies to improve their performance, the study has implications for the design of online crowdsourcing platforms, particularly in terms of incentivizing solvers to put forth their best effort.     

谐波窗分解样本熵与灰色关联度在转子故障识别中的应用

针对实测转子振动信号的非平稳特性和在现实条件中难以获得大量典型故障样本的问题,提出一种基于谐波窗分解(harmonic window decomposition,HWD)、样本熵与灰色关联度相结合的故障识别方法。首先,为了降低噪声的影响,引入循环统计学的思想对传统形态滤波方法进行改进,定义了顺序形态滤波器,并结合实际选用最简单的直线结构元素,对实测转子振动信号进行顺序形态滤波降噪预处理。然后,采用不分层分析的HWD来提取包含转子典型故障信息的6个特征频带,运用非线性动力学参数样本熵作为特征,计算转子正常、不平衡、不对中、油膜涡动、油膜振荡等5种工况的样本熵。最后,由于灰色关联度分析对小样本模式识别具有良好的分类效果,以特征频带的样本熵为元素构造特征向量,通过计算不同振动信号的灰色关联度来判断转子的工作状态和故障类型。试验分析结果表明,所提的方法能够有效地应用于转子系统的故障诊断。     

基于迭代顺序滤波子空间约束的可拒识-支持向量机微钙化点检测

为提高钙化点检测速度,克服微钙化点检测中假阳性高的缺点,本文构造了一种迭代顺序滤波子空间约束的可拒识-支持向量机分类器用于钙化点检测.训练时利用迭代顺序滤波检测作为钙化点的粗检测算子,然后在其约束的子空间内收集非钙化点训练样本.对于输入模式,首先利用基于最大软间隔超平面的支持向量分类器(SVC)进行分类判决;然后对真实的钙化点样本特征空间求取最小的包含球形边界,得到钙化点样本的球形支持向量域表示(SVDD).对于输入模式即可利用钙化点的支持向量域表示进行拒识或接受处理.仿真实验结果表明,本文提出的算法在不影响微钙化点的检出率的情况下,大大提高了检测速度,部分解决了假阳性高的问题.     

基于心理量表的情感图像检索性能评价方法研究

情感图像检索中检索算法优劣的有效评估是一个尚未解决的问题。本文提出基于心理量表的情感图像检索性能评价方法,采用等级排列法或对偶比较法对不同算法检索出的图像进行排序,建立顺序量表,并在样本满足正态分布假设的前提下,将顺序量表转化成等距量表,以比较检索算法的优劣。文中将本实验室实现的情感检索算法检索出的厚重的、简洁的服装图像以及热情的、视野宽广的风景图像与随机检索出的图像进行了比较,验证了基于心理量表的情感图像检索性能评价方法的有效性。     

IP models for round robin tournaments

Generally speaking in sports competition a number of teams play against each other over a period of time according to a certain scheme. The round robin scheme is very popular in many team sports like soccer and basketball. In this paper we study several basic variants of round robin tournaments. Additionally, we examine real world issues that have to be considered when constructing a sports league schedule. We consider constraints imposed by third parties such as security aspects and legal requirements. Moreover, we analyze constraints aiming at attractive and fair sports league schedules. Throughout this paper integer programming models are the means to formally define what the particular problem under consideration is all about. Moreover, the standard solver Cplex is used in order to compute optimal solutions for small- to medium-size instances. Computational results indicate which particular constraint to relax in order to come up with acceptable schedules in reasonable time.     

Score calculation from final tournament tables

In this paper, we deal with the issue of determining the scores of all matches involved in a football tournament. The final table of the tournament, which shows the standings of the teams, is taken as the initial data of the problem. This is a different kind of combinatorial problems which require the construction of valid initial states according to some given final state. We use a rules-based method to solve the problem, analyzing the search space and introducing the notion of black&white graphs. The table data is firstly used to compute possible results of all played matches. Based on the results as well as the total number of scored and conceded goals, possible scores of the matches are then computed. The solution strategy is experimented on several final tables from previous World Cup tournaments. Other experiments are conducted for various team standings, measuring the time required to process some specific data of up to 10 teams.     

政府投资代建制项目双边道德风险的博弈研究

在综合分析代建制下政府投资项目中政府和代建方委托代理关系的基础上,根据委托代理理论,指明无论是委托方还是代理方都有可能单方面做出对自己有利的决策而损害对方利益,发生道德风险;因此运用博弈论的方法建立政府投资代建制项目委托方和代理方之间的博弈模型,并分别从显性激励机制,隐性激励机制以及锦标制度约束双方的视角进行风险防范分析。基于博弈分析的结果,对防止政府投资代建制项目发生道德风险提出了政策建议。     

Scheduling the Italian Football League: an ILP-based approach

Scheduling the Italian Major Football League (the so-called “Serie A”) consists in finding for that league a double round robin tournament schedule that takes into account both typical requirements such as conditions on home-away matches and specific requests of the Italian Football Association such as twin-schedules for teams belonging to the same home-town. In this paper, we present a solution procedure able to derive feasible schedules that are also balanced with respect to additional cable televisions requirements. This procedure adapts the recent approach by Nemhauser and Trick to schedule a College Basketball Conference that considers however only half of the teams involved here. The proposed procedure is divided into three phases: phase 1 generates a pattern set respecting the cable televisions requirements and several other constraints; phase 2 produces a feasible round robin schedule compatible with the above pattern set; finally, phase 3 generates the actual calendar assigning the teams to the patterns. The procedure allows to generate within short time several different reasonable calendars satisfying the cable television companies requirements and satisfying various other operational constraints while minimizing the total number of violations on the home-away matches conditions.     

半素路代数的有向图特征及其应用

用图论的方法讨论有向图△的几何性质及其路代数k（△）的代数性质．论图△不是有向环线弧点图,则△是双侧连接图←→k（△）是素代数,给出了无限和有限竞赛图Hamilton圈存在的路代数条件;给出了半素路代数的有向图特征．     

一种有效的齿轮故障识别方法

针对齿轮故障特征信息往往被信号中的噪声淹没的问题,提出了一种基于谐波小波包、样本熵和灰色关联度的齿轮故障识别方法。首先,采用顺序形态滤波器,并结合实际选用最简单的直线结构元素,对实测齿轮振动信号进行顺序形态滤波降噪预处理。然后,采用谐波小波包将不同故障的齿轮振动信号分解到3层共8个频带上,并计算各频带的样本熵。最后,以样本熵为元素构造特征向量,通过计算标准故障模式特征向量与待识别样本的灰色关联度来判断齿轮的工作状态和故障类型。试验结果表明,该方法能够有效地应用于齿轮系统的故障诊断。