scholarly journals The impact of auction choice on revenue in treasury bill auctions – An empirical evaluation

2017 ◽  
Vol 53 ◽  
pp. 215-239 ◽  
Author(s):  
Daniel Marszalec
2021 ◽  
Vol 11 (2) ◽  
pp. 796
Author(s):  
Alhanoof Althnian ◽  
Duaa AlSaeed ◽  
Heyam Al-Baity ◽  
Amani Samha ◽  
Alanoud Bin Dris ◽  
...  

Dataset size is considered a major concern in the medical domain, where lack of data is a common occurrence. This study aims to investigate the impact of dataset size on the overall performance of supervised classification models. We examined the performance of six widely-used models in the medical field, including support vector machine (SVM), neural networks (NN), C4.5 decision tree (DT), random forest (RF), adaboost (AB), and naïve Bayes (NB) on eighteen small medical UCI datasets. We further implemented three dataset size reduction scenarios on two large datasets and analyze the performance of the models when trained on each resulting dataset with respect to accuracy, precision, recall, f-score, specificity, and area under the ROC curve (AUC). Our results indicated that the overall performance of classifiers depend on how much a dataset represents the original distribution rather than its size. Moreover, we found that the most robust model for limited medical data is AB and NB, followed by SVM, and then RF and NN, while the least robust model is DT. Furthermore, an interesting observation is that a robust machine learning model to limited dataset does not necessary imply that it provides the best performance compared to other models.


Author(s):  
Sandhya Saisubramanian ◽  
Ece Kamar ◽  
Shlomo Zilberstein

Agents operating in unstructured environments often create negative side effects (NSE) that may not be easy to identify at design time. We examine how various forms of human feedback or autonomous exploration can be used to learn a penalty function associated with NSE during system deployment. We formulate the problem of mitigating the impact of NSE as a multi-objective Markov decision process with lexicographic reward preferences and slack. The slack denotes the maximum deviation from an optimal policy with respect to the agent's primary objective allowed in order to mitigate NSE as a secondary objective. Empirical evaluation of our approach shows that the proposed framework can successfully mitigate NSE and that different feedback mechanisms introduce different biases, which influence the identification of NSE.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mahdi Ghaemi Asl ◽  
Muhammad Mahdi Rashidi ◽  
Alireza Ghorbani

Purpose This paper aims to investigate the impact of market structure and market share on the performance of the Islamic banks operating in the Iranian banking system based on the structure-conduct-performance (SCP) paradigm. Design/methodology/approach The Iranian Islamic banking system’s market structure is evaluated by using the econometrics method to test the validity of the traditional SCP paradigm. For this purpose, the authors estimate a simple regression model that is consisted of several independent variables, such as the market share, bank size, real gross domestic product, liquidity and Herfindahl-Hirschman index as a proxy variable for concentration and one dependent variable, namely, the profit as a proxy for performance. The panel data includes a data sample of 22 Islamic banks operating from 2006 to 2019. Data are extracted from the balance sheet of Islamic banks and the time-series database of the Central Bank of Iran and World Bank. Findings The study’s findings indicate that both concentration and market share have a positive impact on the performance of banks in the Iranian Islamic banking system. This result is contradicted with both traditional SCP and efficient structure hypotheses; however, it confirms the existence of oligopoly or cartel in the Iranian Islamic banking system that few banks try to gain the highest share of profit and maintain their market share by colluding with each other. This result is in contradiction with other research studies about the market structure in the Iranian banking system that claimed that banks in Iran operate under monopolistic competition. In addition, it shows that the privatization of some banks in Iran does not improve and help competition in the Iranian banking system. Originality/value This paper is a pioneer empirical study analyzing the market structure, concentration and collusion based on the SCP paradigm in Iranian Islamic banking. The results of the study support the existence of collusive behavior among the Islamic bank in Iran that is not aligned with Sharia. This study clearly shows the difference between ideal Islamic banking and Islamic banking in practice in Islamic countries. This clearly indicates that only prohibiting some operations like receiving interest, gambling and bearing excessive risk is not enough. In fact, the Islamic banking system should be based on the Sharia rule in all aspects and much more modification and study have to be done to achieve an appropriate Islamic banking system. These possible modifications to overcome the issues of cartel-like market structure and collusive behavior in the Iranian Islamic banking system include making the Iranian banking system more transparent, letting foreign banks enter the Iranian banking system and minimizing the government intervention in the Iranian banking system.


Trials ◽  
2015 ◽  
Vol 16 (S2) ◽  
Author(s):  
Royes Joseph ◽  
Julius Sim ◽  
Reuben Ogollah ◽  
Martyn Lewis

2013 ◽  
Vol 427-429 ◽  
pp. 2223-2228
Author(s):  
Xue Bin Wang ◽  
Pei Peng Liu ◽  
Cheng Long Li ◽  
Qing Feng Tan

The I2P network has been widely used to protect user privacy via an open network of onion routers run by volunteers. To the best of our knowledge, the behavior of peers in the I2P network has not been well investigated in the existing researches. In this paper, we first present a simple and effective way to collect peers in the I2P network. Each day over 82% peers has been collected compared to the statistics from the statistics web site. With the data collected, we perform an empirical evaluation, revealing the phenomenon about IP address aliasing and identity aliasing. As identity aliasing makes bad impact on the availability and anonymity of the I2P network, we introduce family concept into the I2P network to mitigate the impact.


2012 ◽  
Vol 58 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Itziar Angulo ◽  
David de la Vega ◽  
Olatz Grande ◽  
Nicoletta Cau ◽  
Unai Gil ◽  
...  

2018 ◽  
Vol 29 (4) ◽  
pp. 740-758 ◽  
Author(s):  
Waqar Ahmed ◽  
Waqar Ahmed ◽  
Arsalan Najmi

PurposeThe concept of green supply chain management (GSCM) is gaining popularity in developing countries due to the environmental and economic impact along with increasing awareness of environmental safety. Enterprises are trying to express their sincere commitment toward green practices. The purpose of this paper is to examine the impact of GSCM on green and economic performance of the firm under the influence of leadership and institutional pressures.Design/methodology/approachConceptual model was developed from previous research works to understand the driving forces of green and economic performance which had inconsistent findings in the literature. Data were collected from 174 leading ISO 14001 certified manufacturing firms in Pakistan by using a structured questionnaire. Partial least squares-structural equation modeling is used for testing the hypotheses.FindingsThe statistical results indicate that the leadership and institutional pressures influence the firm for adoption of internal green practices and external green collaboration. The statistical results also suggest that green practices significantly improve firm’s green and economic performance. However, firm’s external green collaboration does not significantly affect green performance, but it improves green performance significantly.Research limitations/implicationsThis research is conducted on Pakistan as a case of highly populated developing country.Originality/valueThis research presents the empirical evaluation of the influence of leadership and institutional pressure on green practices and improved green and economic performance. The results offer useful understanding for SCM practitioners seeking to adopt GSCM practices. The results also provide policy insights for regulators, organizations and legislators to further promote GSCM.


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