Packing Returning Secretaries

We study online secretary problems with returns in combinatorial packing domains with $n$ candidates that arrive sequentially over time in random order. The goal is to accept a feasible packing of candidates of maximum total value. In the first variant, each candidate arrives exactly twice. All $2n$ arrivals occur in random order. We propose a simple 0.5-competitive algorithm that can be combined with arbitrary approximation algorithms for the packing domain, even when the total value of candidates is a subadditive function. For bipartite matching, we obtain an algorithm with competitive ratio at least $0.5721 - o(1)$ for growing $n$, and an algorithm with ratio at least $0.5459$ for all $n \ge 1$. We extend all algorithms and ratios to $k \ge 2$ arrivals per candidate. In the second variant, there is a pool of undecided candidates. In each round, a random candidate from the pool arrives. Upon arrival a candidate can be either decided (accept/reject) or postponed (returned into the pool). We mainly focus on minimizing the expected number of postponements when computing an optimal solution. An expected number of $\Theta(n \log n)$ is always sufficient. For matroids, we show that the expected number can be reduced to $O(r \log (n/r))$, where $r \le n/2$ is the minimum of the ranks of matroid and dual matroid. For bipartite matching, we show a bound of $O(r \log n)$, where $r$ is the size of the optimum matching. For general packing, we show a lower bound of $\Omega(n \log \log n)$, even when the size of the optimum is $r = \Theta(\log n)$.Comment: 23 pages, 5 figure

Packing Returning Secretaries

We study online secretary problems with returns in combinatorial packing domains with n candidates that arrive sequentially over time in random order. The goal is to accept a feasible packing of candidates of maximum total value. In the first variant, each candidate arrives exactly twice. All 2n arrivals occur in random order. We propose a simple 0.5-competitive algorithm that can be combined with arbitrary approximation algorithms for the packing domain, even when the total value of candidates is a subadditive function. For bipartite matching, we obtain an algorithm with competitive ratio at least 0.5721 - o(1) for growing n, and an algorithm with ratio at least 0.5459 for all n >= 1. We extend all algorithms and ratios to k >= 2 arrivals per candidate. In the second variant, there is a pool of undecided candidates. In each round, a random candidate from the pool arrives. Upon arrival a candidate can be either decided (accept/reject) or postponed (returned into the pool). We mainly focus on minimizing the expected number of postponements when computing an optimal solution. An expected number of Theta(n log n) is always sufficient. For matroids, we show that the expected number can be reduced to O(r log (n/r)), where r <=n/2 is the minimum of the ranks of matroid and dual matroid. For bipartite matching, we show a bound of O(r log n), where r is the size of the optimum matching. For general packing, we show a lower bound of Omega(n log log n), even when the size of the optimum is r = Theta(log n)

Design, Implementation and Evaluation of a National Campaign to Deliver 18 Million Free Long-Lasting Insecticidal Nets to Uncovered Sleeping Spaces in Tanzania.

Since 2004, the Tanzanian National Voucher Scheme has increased availability and accessibility of insecticide-treated nets (ITNs) to pregnant women and infants by subsidizing the cost of nets purchased. From 2008 to 2010, a mass distribution campaign delivered nine million long-lasting insecticidal nets (LLINs) free-of-charge to children under-five years of age in Tanzania mainland. In 2010 and 2011, a Universal Coverage Campaign (UCC) led by the Ministry of Health and Social Welfare (MoHSW) was implemented to cover all sleeping spaces not yet reached through previous initiatives. The UCC was coordinated through a unit within the National Malaria Control Programme. Partners were contracted by the MoHSW to implement different activities in collaboration with local government authorities. Volunteers registered the number of uncovered sleeping spaces in every household in the country. On this basis, LLINs were ordered and delivered to village level, where they were issued over a three-day period in each zone (three regions). Household surveys were conducted in seven districts immediately after the campaign to assess net ownership and use. The UCC was chiefly financed by the Global Fund to Fight AIDS, Tuberculosis and Malaria with important contributions from the US President's Malaria Initiative. A total of 18.2 million LLINs were delivered at an average cost of USD 5.30 per LLIN. Overall, 83% of the expenses were used for LLIN procurement and delivery and 17% for campaign associated activities. Preliminary results of the latest Tanzania HIV Malaria Indicator Survey (2011-12) show that household ownership of at least one ITN increased to 91.5%. ITN use, among children under-five years of age, improved to 72.7% after the campaign. ITN ownership and use data post-campaign indicated high equity across wealth quintiles. Close collaboration among the MoHSW, donors, contracted partners, local government authorities and volunteers made it possible to carry out one of the largest LLIN distribution campaigns conducted in Africa to date. Through the strong increase of ITN use, the recent activities of the national ITN programme will likely result in further decline in child mortality rates in Tanzania, helping to achieve Millennium Development Goals 4 and 6

For Our Information, June 1958, Vol. X, no. 9

An official publication of the ILR School, Cornell University, “for the information of all faculty, staff and students.

The creation of the Faculty of Community Medicine (now the Faculty of Public Health Medicine) of the Royal Colleges of Physicians of the United Kingdom

The National Health Service Act 1946 transferred responsibility for the non-voluntary hospitals and certain clinical services from the public health departments of counties and county boroughs to new regional hospital boards, thereby substantially reducing the functions of their medical officers of health and creating a separate cadre of doctors concerned with the planning and management of hospital and specialist services. At around the same time there was pressure to develop in each medical school a department of social and preventive medicine with full-time staff involved in research work. Reviewing the situation 20 years later, the Royal Commission on Medical Education recommended that doctors in public health, medical administration or related teaching and research should form a single professional body concerned with the assessment of specialist training for and standards of practice in 'community medicine'. Immediately after the publication of the Commission's Report in 1968, J. N. Morris invited leaders in the three strands of activities to meet and discuss the proposal. A series of informal meetings led to the setting up, in 1969, of a Working Party (chairman, J. N. Morris) which negotiated with the Royal Colleges of Physicians of Edinburgh, Glasgow and London for them to create a faculty of community medicine. In November 1970 the Colleges set up a Provisional Council (chairman, W. G. Harding), later Board, and the Faculty formally came into existence on 15 March 1972. The key decisions and some of the complications and hitches encountered in achieving this radical outcome are described in this paper

\u27A Blood-Stained Corpse in the Butler\u27s Pantry’: The Queensland Bush Book Club

Lending libraries were not the norm in 1934 when the Carnegie Corporation of New York sent American librarian, Ralph Munn, to conduct a study of the condition of Australian libraries. In his initial survey Munn learned of the Queensland Bush Book Club, an organization of well-to-do, philanthropic women from Brisbane who had established a book lending service for settlers in the Outback. They hoped to ease the drudgery and lighten the burden faced by isolated women and their families in the rural areas. The antidote was a regular parcel of “proper” reading matter which included books, newspapers and magazines. They took advantage of a well-developed railway system to deliver the packages to rural families. Testimonials found in the Queensland Bush Book Club annual reports provide a snapshot of frontier life detailing drought, fire, flood and all manner of misfortune and privation. The reports also offer specifics of the type of books the settlers requested and the gratitude with which the parcels were received. Murder mysteries were at the top of the request list, as the title of this article suggests. This article also examines the relationships forged between town and country residents around the distribution of books, and the mechanics involved in providing a book lending service before free public libraries became commonplace

The United States and China

Includes American Prospects in China, by T.C. White. Extract from The Overland Monthly, San Francisco, vol.57, no.5, May 1911, 19 pages.https://digitalrepository.trincoll.edu/moore/1074/thumbnail.jp

The Athlete, August 1986

https://encompass.eku.edu/athlete/1312/thumbnail.jp