Voltage security evaluation based on perturbation method

This is the post-print version of the final paper published in International Journal of Electrical Power & Energy Systems. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2009 Elsevier B.V.This paper proposes a new algorithm for estimating voltage security margin. The algorithm is based on the perturbation method and has significant computational efficiency. The proposed algorithm can be used for on-line voltage security evaluation. It has been validated using IEEE-14, IEEE-30 and IEEE-57 bus systems. Results from the tests show higher efficiency and smaller error margins compared to continuation power flow (CPF) method. Voltage collapse is a serious threat to the security of stressed power systems; therefore, voltage security (VS) has become a major challenge for management of power systems. The motivation for this research is a direct consequence of the deregulation of electricity industries and markets worldwide

Desire for Information and Preference for Participation in Treatment Decisions in Patients With Cancer Presenting to the Department of General Surgery in a Tertiary Care Hospital in India

Purpose: Providing appropriate information to patients about their illness helps them to cope with the diagnosis. Shared decision making is a key concept in managing patients with cancer. There are no data available about the desire for information and preference for participation in treatment decisions among Indian patients with cancer. The objective of this study was to estimate the proportion of patients who have information needs and to study the patient preference for participation in treatment decisions and the factors associated with them. Methods: A cross-sectional survey was conducted among patients with cancer older than 18 years. They were interviewed with a questionnaire after signing an informed consent. The association of sex, educational level, residence, diagnosis (type of cancer), Eastern Cooperative Oncology Group performance status, and treatment status with information needs and decision-making preference was analyzed using χ2 test Results: Approximately 81% of patients said that they had an absolute need to know if the illness was cancer, and > 70% of patients either had an absolute need to know or would like to know about the prognosis, treatment options, and adverse effects. Regarding the decision-making preferences, 97% wanted their treating physicians to make the decision regarding their treatment, and 66% preferred to share decision making with their family. Conclusion: The majority of the patients with cancer expressed a need for knowing whether they had cancer. When it comes to treatment decisions, most of them preferred a passive role, and the majority wanted to involve their families in the decision-making process. We recommend that the treating physician should elicit the patient’s preference in participating in treatment decisions and their preference about involving their family in making treatment decision