Clustering Algorithm Based on Sparse Feature Vector without Specifying Parameter

Parameter setting is an essential factor affecting algorithm performance in data mining techniques. CABOSFV is an efficient clustering algorithm which can cluster binary data with sparse features, but it is challenging to specify the threshold parameter. To solve the difficulty of parameter decision, a clustering algorithm based on sparse feature vector without specifying parameter (CASP) is proposed in this paper. The calculation method of an upper limit of threshold is firstly defined to determine the range of threshold. Furthermore, we use the sparseness index to sort the data and conduct the clustering process based on the adjusted sparse feature vector after data sorting. An interval search strategy is adopted to find a suitable threshold within the defined threshold range, and the clustering result with the selected suitable parameter is the outcome. Experiments on 7 UCI datasets demonstrate that the clustering results of the CASP algorithm are superior to other baselines in terms of both effectiveness and efficiency. CASP not only simplifies the parameter decision process, but also obtains desirable clustering results quickly and stably, which shows the practicability of the algorithm

Understanding the Evaluation Abilities of External Cluster Validity Indices to Internal Ones

Evaluating internal Cluster Validity Index (CVI) is a critical task in clustering research. Existing studies mainly employ the number of clusters (NC-based method) or external CVIs (external CVIs-based method) to evaluate internal CVIs, which are not always reasonable in all scenarios. Additionally, there is no guideline of choosing appropriate methods to evaluate internal CVIs in different cases. In this paper, we focus on the evaluation abilities of external CVIs to internal CVIs, and propose a novel approach, named external CVI\u27s evaluation Ability MEasurement approach through Ranking consistency (CAMER), to measure the evaluation abilities of external CVIs quantitatively, for assisting in selecting appropriate external CVIs to evaluate internal CVIs. Specifically, we formulate the evaluation ability measurement problem as a ranking consistency task, by measuring the consistency between the evaluation results of external CVIs to internal CVIs and the ground truth performance of internal CVIs. Then, the superiority of CAMER is validated through a real-world case. Moreover, the evaluation abilities of seven popular external CVIs to internal CVIs in six different scenarios are explored by CAMER. Finally, these explored evaluation abilities are validated on four real-world datasets, demonstrating the effectiveness of CAMER

Clinical analysis of vulvar cancer

Background: The purpose of this study is to understand the incidence, related factors, and the prognosis factors in order to avoid risk, proper method of diagnosis and treatment and reduce complications and provide the basis.Methods: 85 Vulvar cancer (VC) patients treated in our hospital from 2002.10 to 2012.10 were collected and analyzed by retrospective comparative methods. SPSS19.0 application software was used for the statistical analysis. The clinical data are analyzed by chi-square and F test statistic methods. P < 0.05 was a significant difference between the judgment standard.Results: During 10 years, we treated 3391 cases of the primary malignant tumors including 85 VC cases; VC was 2.89% (85/3391). The age was between 24～88 years old, mean was 57.09±12.93 yrs. old, variable age of the VC had been juvenescence trend (F=6. 013，P=0.016＜0.05＝). The differences between the urban and rural residential area have some influence to the onset of VC. Rural patients are more than urban patients. By statistical analysis, region distribution in these two groups was remarkably different=4.16，P=0.045＜0.05, but the urban proportion of patients in different years has no difference（χ2=0.080, P=0.777）.Conclusion: The number of cases increased progressively in young age. VC patients were more in rural area than urban. History of malignant tumor and obesity has the positive correlation with VC. High-risk groups should be alert to the possibility of VC. Preoperative diagnosis should be Colposcopic, biopsy in order to improve the accuracy of earlier diagnosis. Vulvar resects have an effect on the healing of the incision. Follow-up rate is low; It is difficult to say statistically survival rate is 5 years

Competition, markups, and gains from trade: A quantitative analysis of China between 1995 and 2004

Sing Lun Fellowship of Singapore Management Universit

Competition and Gains from Trade: A Quantitative Analysis of China Between 1995 and 2004

SMU Economics and Statistics Working Paper Series, Paper No. 13-2015</p

Wrong Skewness and Finite Sample Correction

In parametric stochastic frontier models, the composed error is specified as the sum of a two-sided noise component and a one-sided inefficiency component, which is usually assumed to be half-normal, implying that the error distribution is skewed in one direction. In practice, however, estimation residuals may display skewness in the wrong direction. Model re-specification or pulling a new sample is often prescribed. Since wrong skewness is considered a finite sample problem, this paper proposes a finite sample adjustment to existing estimators to obtain the desired direction of residual skewness. This provides another empirical approach to dealing with the so-called wrong skewness problem

The Influence of Pelvic Ramus Fracture on the Stability of Fixed Pelvic Complex Fracture

This study aims to evaluate the biomechanical mechanism of pelvic ring injury for the stability of pelvis using the finite element (FE) method. Complex pelvic fracture (i.e., anterior column with posterior hemitransverse lesion) combined with pelvic ramus fracture was used to evaluate the biomechanics stability of the pelvis. Three FE fracture models (i.e., Dynamic Anterior Plate-Screw System for Quadrilateral Area (DAPSQ) for complex pelvic fracture with intact pubic ramus, DAPSQ for complex pelvic fracture with pubic ramus fracture, and DAPSQ for complex pelvic fracture with fixed pubic ramus fracture) were established to explore the biomechanics stability of the pelvis. The pubic ramus fracture leads to an unsymmetrical situation and an unstable situation of the pelvis. The fixed pubic ramus fracture did well in reducing the stress levels of the pelvic bone and fixation system, as well as displacement difference in the pubic symphysis, and it could change the unstable situation back to a certain extent. The pelvic ring integrity was the prerequisite of the pelvic stability and should be in a stable condition when the complex fracture is treated

Implications of global carbon governance for corporate carbon emissions reduction

Global warming not only affects biodiversity, but also threatens human health and wellbeing. As the main source of greenhouse gas emissions, enterprises play a critical role in carbon emissions reduction. However, only a small number of enterprises have disclosed their “low-carbon transition roadmap”, primarily due to the lack of immediate payoffs of green investment, which is disadvantageous to achieve net-zero emissions. First, through case analysis of carbon governance in typical countries around the world, we identify effective emissions reduction measures that firms can learn from. Next, this paper summarizes the multi-dimensional impact framework of corporate carbon emissions reduction. Last, we propose a carbon emissions reduction roadmap for companies from four aspects: companies should 1) actively engage in the carbon emissions trading system, 2) increase the application of green technology, 3) enhance corporate governance structure, and 4) ensure sufficient cash flow for low-carbon transition. This study contributes to the framework of corporate sustainable transition, providing practical references for balancing corporate environmental footprint and value growth

Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is designed to meet the basic cabinet cooling demand, the additional parallel branch of battery chiller is a good way to solve the battery group cooling problem, which can supply about 20% additional cooling capacity without input power increase. Its coefficient of performance for cabinet heating is around 1.34 at −20 °C out-car temperature and 20 °C in-car temperature. The specific heat of the battery group is tested about 1.24 kJ/kg °C. There exists a necessary temperature condition for the heat pipe heat exchanger to start action. The heat pipe heat transfer performance is around 0.87 W/°C on cooling mode and 1.11 W/°C on preheating mode. The gravity role makes the heat transfer performance of the heat pipe on preheating mode better than that on cooling mode