The classification of HLA supertypes by GRID/CPCA and hierarchical clustering methods

Biological experiments often produce enormous amount of data, which are usually analyzed by data clustering. Cluster analysis refers to statistical methods that are used to assign data with similar properties into several smaller, more meaningful groups. Two commonly used clustering techniques are introduced in the following section: principal component analysis (PCA) and hierarchical clustering. PCA calculates the variance between variables and groups them into a few uncorrelated groups or principal components (PCs) that are orthogonal to each other. Hierarchical clustering is carried out by separating data into many clusters and merging similar clusters together. Here, we use an example of human leukocyte antigen (HLA) supertype classification to demonstrate the usage of the two methods. Two programs, Generating Optimal Linear Partial Least Square Estimations (GOLPE) and Sybyl, are used for PCA and hierarchical clustering, respectively. However, the reader should bear in mind that the methods have been incorporated into other software as well, such as SIMCA, statistiXL, and R.

Who “likes” you … and why? A typology of Facebook fans

Although many managers recognize that Facebook Fans represent a marketing opportunity, there has been little research into the nature of different Fan types. This study explores a typology of Fans, drawn from a sample of 438 individuals who "Like" brands on Facebook. Fans' brand loyalty, brand love, use of self-expressive brands, and word of mouth (WOM) for Liked brands were used to suggest four Fan types: the "Fan"-atic, the Utilitarian, the Self-Expressive, and the Authentic. The results of this exploratory study highlight the value of cluster analysis as a strategy for identifying different Fan types and provide insights to prompt further research into Facebook Fan types.

Integrating skills profiling and purchasing portfolio management:an opportunity for building purchasing capability

Kralijc’s (1983) purchasing portfolio approach holds that different types of purchases need different sourcing strategies, underpinned by distinct sets of resources and practices. The approach is widely deployed in business and extensively researched, and yet little research has been conducted on how knowledge and skills vary across a portfolio of purchases. This study extends the body of knowledge on purchasing portfolio management, and its application in the strategic development of purchasing in an organization, and on human resource management in the purchasing function. A novel approach to profiling purchasing skills is proposed, which is well suited to dynamic environments which require flexibility. In a survey, experienced purchasing personnel described a specific purchase and profiled the skills required for effective performance in purchasing that item. Purchases were categorized according to their importance to the organization (internally-oriented evaluation of cost and production factors) and to the supply market (externally-oriented evaluation of commercial risk and uncertainty). Through cluster analysis three key types of purchase situations were identified. The skills required for effective purchasing vary significantly across the three clusters (for 22 skills, p<0.01). Prior research shows that global organizations use the purchasing portfolio approach to develop sourcing strategies, but also aggregate analyses to inform the design of purchasing arrangements (local vs global) and to develop their improvement plans. Such organizations would also benefit from profiling skills by purchase type. We demonstrate how the survey can be adapted to provide a management tool for global firms seeking to improve procurement capability, flexibility and performance.

The New Software Package for Dynamic Hierarchical Clustering for Circles Types of Shapes

In data mining, efforts have focused on finding methods for efficient and effective cluster analysis in large databases. Active themes of research focus on the scalability of clustering methods, the effectiveness of methods for clustering complex shapes and types of data, high-dimensional clustering techniques, and methods for clustering mixed numerical and categorical data in large databases. One of the most accuracy approach based on dynamic modeling of cluster similarity is called Chameleon. In this paper we present a modified hierarchical clustering algorithm that used the main idea of Chameleon and the effectiveness of suggested approach will be demonstrated by the experimental results.

Knowledge workers and their relationships with organisations

The programme of research examines knowledge workers, their relationships with organisations, and perceptions of management practices through the development of a theoretical model and knowledge worker archetypes. Knowledge worker and non-knowledge worker archetypes were established through an analysis of the extant literature. After an exploratory study of knowledge workers in a small software development company the archetypes were refined to include occupational classification data and the findings from Study 1. The Knowledge Worker Characteristics Model (KWCM) was developed as a theoretical framework in order to analyse differences between the two archetypes within the IT sector. The KWCM comprises of the variables within the job characteristics model, creativity, goal orientation, identification and commitment. In Study 2, a global web based survey was conducted. There were insufficient non-knowledge worker responses and therefore a cluster analysis was conducted to interrogate the archetypes further. This demonstrated, unexpectedly, that that there were marked differences within the knowledge worker archetypes suggesting the need to granulate the archetype further. The theoretical framework and the archetypes were revised (as programmers and web developers) and the research study was refocused to examine occupational differences within knowledge work. Findings from Study 2 identified that there were significant differences between the archetypes in relation to the KWCM. 19 semi-structured interviews were conducted in Study 3 in order to deepen the analysis using qualitative data and to examine perceptions of people management practices. The findings from both studies demonstrate that there were significant differences between the two groups but also that job challenge, problem solving, intrinsic reward and team identification were of importance to both groups of knowledge workers. This thesis presents an examination of knowledge workers’ perceptions of work, organisations and people management practices in the granulation and differentiation of occupational archetypes.

Benefit segmentation of international travelers to Macau, China

The purpose of this study is threefold: (1) to identify the underlying benefits sought by international visitors to Macau, China, which has emerged as a popular gambling destination in Asia; (2) to segment tourists visiting Macau by employing a cluster analysis based on the benefits sought; and (3) to examine any salient differences between the segment groups with regard to their behavioral characteristics, socio-economic characteristics, and demographic profiles. A convenience sample was used to collect data in the Macau International Airport, in the Macau Ferry Terminal, and at the border gate with Mainland China. A total 1,513 useful surveys were retained for data analysis. Cluster analysis discloses four distinct clusters: "convention and business seekers," "family and vacation seekers," "gambling and shopping seekers," and "multi-purpose seekers." Based on the results of our findings, several managerial implications are discussed. © Taylor & Francis Group, LLC.

Extraction of Fraud Schemes from Trade Series

2000 Mathematics Subject Classification: 62H30, 62M10, 62M20, 62P20, 94A13.

A Statistical Approach for Multilingual Document Clustering and Topic Extraction from Clusters

2000 Mathematics Subject Classification: 62H30

Classification of Chenopodium Genus Populations and Species Based on Continuous and Categorical Variables

2000 Mathematics Subject Classification: 62P10, 62H30

Study of the Self-Assessment as а Component of the Model of Self-Regulated Learning for Engineering Students

Report published in the Proceedings of the National Conference on "Education and Research in the Information Society", Plovdiv, May, 2015

Inventory investment and sectoral characteristics in some OECD countries

This paper discusses the effects of sectoral structure on the long run macroeconomic inventory behaviour of national economies. Data on 15 OECD countries are included in the analysis, which is based on correlation and cluster analysis methodologies. The study is part of a long-term research project exploring factors influencing the inventory behaviour of national economies. First, we introduce some basic characteristics of macroeconomic inventory formation in the 15 OECD countries. We argue that our previous results on the existence of specific characteristic features of macroeconomic inventory investment are justified, hence it makes sense to study the factors influencing these features. We then examine the contribution of various sectors to the production of in the countries involved and the relationship between sectoral structure and inventory intensity (annual inventory change/Gross Value Added). We find that the high share of agriculture and manufacturing increases inventory intensity, that the increasing share of services has a negative effect and that the role of construction and trade is not obvious. The relatively low stability of the statistical results warns us to be cautious with our judgements. Further, case-by-case analysis would be required to obtain more solid results.

Az exportteljesítmények és a hátterükben álló vállalati jellemzők elemzése (Export performance clusters of the Hungarian enterprises)

A tanulmány célja a Magyarországon működő exportáló vállalatok jellemzőinek feltárása volt a 2009-es vállalati versenyképességi felmérés alapján. Több tanulmány vizsgálta a vállalatok exportteljesítményét vállalati méret és tulajdonosi szerkezet szerinti bontásban, az elemzésben a szerző viszont ettől eltérő szemléletmódot alkalmazott. A vállalatok exportteljesítménye áll (exportértékesítés volumene, aránya, exportárbevétel változása, jövedelmezőség), a vállalati csoportképzés, klaszterelemzés középpontjában. Három jól elkülöníthető klasztert sikerült azonosítani: a jelentős exporthányaddal és folyamatos növekedéssel jellemezhető sikeres exportáló vállalatok csoportját, a stagnálással, s gyakran csökkenő exportértékesítéssel jellemezhető vállalatcsoportot, s végül a harmadik klasztert azok a jelenleg még alacsony export-ár bevétellel és alacsony exportaránnyal jellemezhető vállalatok képezték, melyekre a növekedés és a kiugróan magas jövedelmezőség volt a jellemző. Az elemzés egyediségét az adja, hogy a vállalati versenyképességi felmérés adatbázisa lehetővé tette a különböző exportteljesítmények hátterében álló működési jellemzők vizsgálatát, amelynek eredményeit a cikk bemutatja. Fő következtetésként megállapítható, hogy a sikeres exportáló vállalatok csoportja mindegyik jellemző szerint jobb működési jellemzőkkel rendelkezik a másik két csoporthoz viszonyítva. / === / The purpose of the paper is to reveal the main characteristics of the Hungarian export oriented firms. It is based on the Hungarian Competitiveness Research Survey 2009. 85% of enterprises were small or medium size in the sample. The aim of the analysis was to identify main factors and tendencies of the overall export performance. Several papers discussed the export activities of firms according to their size and ownership structure in Hungary. A different method was used here. The overall export performance (measured by volume, change, and share of export revenues, and firm profitability ratios) was put in the centre of cluster analysis. Three different clusters were identified. Firms in the firstcluster had significant export performance and growth rate. The second cluster was the group of stagnating firms and the third one contained those whose export performance was low but signaled growth with excellent profitability ratios. The uniqueness of the paper derived from the Competitiveness Research Survey because it provided an opportunity to analyse the connection between export performance and other management and operational characteristics of enterprises. The paper may induce futher research in exploring main enterprise level factors of export performance of the Hungarian firms.

A fiatalok fogyasztási és életmódbeli szokásai a környezeti nevelés tükrében

A tanulmány egy olyan kutatás mélyebb elemzésének eredményeit mutatja be, amelynek során a Budapesti Corvinus Egyetem Környezetgazdaságtani és Technológiai Tanszékének munkatársai kérdőíves felmérést hajtottak végre a Norvég Alap támogatásával, a „Fenntartható fogyasztás, termelés és kommunikáció” c. projekt keretében. A válaszok alapján összehasonlíthatjuk a fiatalok egyes csoportjainak környezettudatosságát és a fogyasztáshoz való viszonyát, amelynek alapján meghatározhatjuk a környezeti nevelés legfontosabb fókuszait és eszközeit. Két iskolatípus (egyetemisták és középiskolások) tanulóinak adatai alapján többdimenziós skálázás segítségével vizsgáltuk azt, hogy a diákokat leíró jellemzők közül melyek mozognak együtt, és melyek előfordulása mutat ellentétes irányba. Klaszterelemzéssel azt is feltártuk, hogy a mintába került személyek milyen hasonlóságokat és eltéréseket mutatnak, milyen, többé-kevésbé homogén csoportok képezhetők belőlük. Az eredmények alapján szakmai javaslatokat fogalmazunk meg a környezeti nevelés területére. _______ This paper presents the in-depth analysis of results from a survey of students from secondary and tertiary education. The survey was conducted by researchers from the department of environmental economics and technology of the Corvinus University of Budapest in the framework of the project titeld „sustainable consumption, production and communication” supported by the Norwegian Fund. The environmental consciousness and consumer behaviour of different groups of young people are compared, allowing identification of the main focus points and tools of environmental education. Multidimensional scaling is used to examine which characteristics of the students are related and which point in opposite directions. Similarities and differences between respondents were mapped through cluster analysis and relatively homogeneous groups were indentified. The results are used to make suggestions for the development of environmental education.

Értékteremtés e-kereskedelemmel – kitörési lehetőség a recesszió sújtotta magyar kiskereskedelemben? (Value creation of e-commerce – Chance to break out for the recession-hit Hungarian retail sector?)

Kimutatható-e az e-kereskedelem hatása a vállalati teljesítményre a recesszióval küzdő magyar kiskereskedelmi piacon? A hagyományos bolti értékesítés vagy on-line kereskedelem vezet hazánkban jobb pénzügyi teljesítményhez? Ezekre a kérdésekre a magyar IKT (infokommunikációs technológiai) kiskereskedők 187 elemű mintáján igyekeznek a szerzők választ keresni, az adatgyűjtést újszerű módon részben automatizált webpókokra bízva, következtetéseiket pedig elsősorban klaszterelemzési technikákra építve. Megállapítják, hogy bár a legjobb bolti kereskedők többnyire valamivel nagyobb és stabilabb profitrátákkal jellemezhetők a válság éveiben is, a piac megtartása és növelése terén már egyértelműen az e-kereskedők jeleskedtek. Eredményeik szerint az e-kereskedelem hozzásegítheti a kiskereskedőket a munkaerő-hatékonyság növeléséhez is, ám ha gyors rendelkezésre állással vagy alacsony árakkal csábítják vevőiket, akkor a profittöbblet egy részét felőrölheti a magasabb készlettartási igény vagy az árverseny. _____ The study examines whether e-commerce has a significant impact on corporate performance on the Hungarian retail market struggling with the effects of economic downturn. Is it brick-and-mortal retail or e-commerce that leads to a better financial performance? Using the innovative data gathering tools of automotive web crawlers the authors seek answers to these questions on a sample of 187 Hungarian ICT retailers. Based on cluster analysis they conclude that while the best traditional retailers have somewhat higher and more stable profitability ratios even during the years of recession, e-tailers are more successful in retaining and increasing their market share. E-commerce is also associated with higher human resource productivity, but the possible profit surplus originating from this advantage could be jeopardized in the long run as new electronic traders typically attract their customers by shorter service time or lower prices.