Engin Sungur - Academia.edu (original) (raw)

Papers by Engin Sungur

Communications in Statistics-theory and Methods, 2005

ABSTRACT In this article, we define and study the concept of directional dependence in bivariate ... more ABSTRACT In this article, we define and study the concept of directional dependence in bivariate regression setting by using copulas. We consider two cases of directional dependence; one originating from marginals and the other originating from the joint ...

Communications in Statistics-theory and Methods, 1996

In this paper the concept of diagonal copulas is introduced and its properties are examined. It i... more In this paper the concept of diagonal copulas is introduced and its properties are examined. It is shown that for the Archimedean class, the diagonal copula uniquely determines the corresponding copula. This fact helps to reduce the dimension and makes it easier to ...

American Statistician, 1999

Statistics instructors know that interesting, real-world problems are crucial to motivate student... more Statistics instructors know that interesting, real-world problems are crucial to motivate student learning. As an extension of our efforts to build student interest and ownership in applications, we recently incorporated service learning into our statistics courses. Service learning provides an active-learning experience associated with a community service application. In this article we describe our experiences using service learning in our statistics courses. We give examples of projects used at the University of Minnesota-Morris, a public, liberal arts college.

Communications in Statistics-theory and Methods, 2002

ABSTRACT In this paper, m-dimensional distribution functions with truncation invariant dependence... more ABSTRACT In this paper, m-dimensional distribution functions with truncation invariant dependence structure are studied. Some of the properties of generalized Archimedean class of copulas under this dependence structure are presented including some results on the ...

Communications in Statistics-theory and Methods, 1991

The lower dimensional marginal density functions of a truncated multivariate density function is ... more The lower dimensional marginal density functions of a truncated multivariate density function is derived in general, and shown that it is a function of untruncated marginal density function, appropriately defined conditional distribution function and size of the multivariate truncation region. As a special case, lower dimensional marginal density function of a truncated multivariate normal distribution is given.

Quantitative Structure-activity Relationships, 1991

A congeneric set of 2,5-disubstituted benzoxazole (III) and 2-substituted oxazolo(4,5-b)pyridine ... more A congeneric set of 2,5-disubstituted benzoxazole (III) and 2-substituted oxazolo(4,5-b)pyridine (IV) derivatives 1–46, previously tested for their antifungal activity against C. albicans, were analyzed by quantitative structure-activity relationship (QSAR) techniques. The activity contributions for either ring system or substituent effects were determined from the correlation equations, and the predictions of the potent antifungally active derivatives were described by the results obtained from the computer-assisted stepwise regression procedure. The resulting QSAR revealed that oxazolo(4,5-b) pyridine ring system was more preferable than benzoxazole and the benzyl group at position 2 was more significant than the corresponding phenyl substituent. Although the para substitution of benzyl or phenyl moiety with electron donating/withdrawing groups was neglectable, the nature of the substituents at the 5th position (R1) of the fused ring system was important for the potency. Substituting this position with electron withdrawing groups like nitro produces an increase in the antifungal activity.

Communications in Statistics-theory and Methods, 2005

ABSTRACT In this article, we define and study the concept of directional dependence in bivariate ... more ABSTRACT In this article, we define and study the concept of directional dependence in bivariate regression setting by using copulas. We consider two cases of directional dependence; one originating from marginals and the other originating from the joint ...

Communications in Statistics-theory and Methods, 1996

In this paper the concept of diagonal copulas is introduced and its properties are examined. It i... more In this paper the concept of diagonal copulas is introduced and its properties are examined. It is shown that for the Archimedean class, the diagonal copula uniquely determines the corresponding copula. This fact helps to reduce the dimension and makes it easier to ...

American Statistician, 1999

Statistics instructors know that interesting, real-world problems are crucial to motivate student... more Statistics instructors know that interesting, real-world problems are crucial to motivate student learning. As an extension of our efforts to build student interest and ownership in applications, we recently incorporated service learning into our statistics courses. Service learning provides an active-learning experience associated with a community service application. In this article we describe our experiences using service learning in our statistics courses. We give examples of projects used at the University of Minnesota-Morris, a public, liberal arts college.

Communications in Statistics-theory and Methods, 2002

ABSTRACT In this paper, m-dimensional distribution functions with truncation invariant dependence... more ABSTRACT In this paper, m-dimensional distribution functions with truncation invariant dependence structure are studied. Some of the properties of generalized Archimedean class of copulas under this dependence structure are presented including some results on the ...

Communications in Statistics-theory and Methods, 1991

The lower dimensional marginal density functions of a truncated multivariate density function is ... more The lower dimensional marginal density functions of a truncated multivariate density function is derived in general, and shown that it is a function of untruncated marginal density function, appropriately defined conditional distribution function and size of the multivariate truncation region. As a special case, lower dimensional marginal density function of a truncated multivariate normal distribution is given.

Quantitative Structure-activity Relationships, 1991

A congeneric set of 2,5-disubstituted benzoxazole (III) and 2-substituted oxazolo(4,5-b)pyridine ... more A congeneric set of 2,5-disubstituted benzoxazole (III) and 2-substituted oxazolo(4,5-b)pyridine (IV) derivatives 1–46, previously tested for their antifungal activity against C. albicans, were analyzed by quantitative structure-activity relationship (QSAR) techniques. The activity contributions for either ring system or substituent effects were determined from the correlation equations, and the predictions of the potent antifungally active derivatives were described by the results obtained from the computer-assisted stepwise regression procedure. The resulting QSAR revealed that oxazolo(4,5-b) pyridine ring system was more preferable than benzoxazole and the benzyl group at position 2 was more significant than the corresponding phenyl substituent. Although the para substitution of benzyl or phenyl moiety with electron donating/withdrawing groups was neglectable, the nature of the substituents at the 5th position (R1) of the fused ring system was important for the potency. Substituting this position with electron withdrawing groups like nitro produces an increase in the antifungal activity.