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Thesis (M.S.)--Ohio State University, 1985. / Includes bibliographical references (leaves 72-79). Available online via OhioLINK's ETD Center

Pruning has been used to reduce tree size, allow light penetration into trees, improve yield, improve fruit size and fruit quality, overcome alternate bearing, assist fruit harvest, and assist pest and disease control. The use of pruning has increased due to improving agricultural management techniques such as high planting densities, use of mechanical machinery in orchards and the need for effective pesticide and pathological chemical spray applications. The main objective of this study was to obtain a practical means of manipulating lemon trees at the right time. Pruning at the correct time to cultivate productive trees that produce quality fruit would have financial benefits. Lemon fruit quality is dependent on market demand and involves a number of features such as fruit shelf life, rind thickness, fruit size, rind colour, and juice content. The study was conducted on ’Eureka’ lemon trees budded on C. volkameriana rootstock, bearing the fifth and sixth commercial crops in 1999 and 2000 respectively. Twelve monthly pruning treatments per year were conducted on one row of trees starting in December 1997 (site 1) and repeated in the second year on the adjacent row of the same orchard starting in December 1998 (site 2). Selective pruning heading cuts were applied below the intercalation on the intercalary units. Potential branch bearing units were tagged and assessed during the harvest and flowering periods. Summer pruning between 16 to 19 months before the subsequent April/May harvest, resulted in the longest and most complex (intercalation sprouted per axil) vegetative response. The estimated crop value indicated that summer pruning treatments produced the highest income. This was ascribed not to differences in fruit size or quality, but to an increase in yield. The industry’s trend is to prune citrus from post-harvest to the pre-bloom stage. Results from this study have provided a beneficial cultural practice to prune during the summer months and provides a practice to optimise farm production and profit margins.

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The increasing amount of electronically available information in society today is undeniable. Examples include the numbers of general web pages, scientific publications, and items in online auctions. From a user's perspective, this trend will lead to information overflow. Moreover, information publishers are compromised by this situation, as users have greater difficulty in identifying useful information. Publish-subscribe systems can be applied to cope with the reality of information overflow. In these systems, users specify their information interests as subscriptions and, subsequently, only matching information (event messages) is delivered; uninteresting information is filtered out before reaching users. In this dissertation, we consider content-based publish-subscribe systems, a sophisticated example of these systems. They perform the information-filtering task based on the content of provided information. In order to deal with high numbers of subscriptions and frequencies of event messages, publish-subscribe systems are realized as distributed systems. Advertisements---publisher specifications of potential future event messages---are optionally applied in these systems to reduce the internal distribution of subscriptions. Existing work on content-based publish-subscribe concepts mainly focuses on subscriptions and advertisements as pure conjunctive expressions. Therefore, subscriptions or advertisements using operators other than conjunction need to be canonically converted to disjunctive normal form by these systems. Each conjunctive component is then treated as individual subscription or advertisement. Unfortunately, the size of converted expressions is exponential in the worst case. In this dissertation, we show that the direct support of general Boolean subscriptions and advertisements improves the time and space efficiency of general-purpose content-based publish-subscribe systems. For this purpose, we develop suitable approaches for the filtering and routing of general Boolean expressions in these systems. Our approaches represent solutions to exactly those components of content-based publish-subscribe systems that currently restrict subscriptions and advertisements to conjunctive expressions. On the subscription side, we present an effective generic filtering algorithm, and a novel approach to optimize event routing tables, which we call subscription pruning. To support advertisements, we show how to calculate the overlap between subscriptions and advertisements, and introduce the first designated subscription routing optimization, which we refer to as advertisement pruning. We integrate these approaches into our prototype BoP (BOolean Publish-subscribe) which allows for the full support of general Boolean expressions in its filtering and routing components. In the evaluation part of this dissertation, we empirically analyze our prototypical implementation BoP and compare its algorithms to existing conjunctive solutions. We firstly show that our general-purpose Boolean filtering algorithm is more space- and time-efficient than a general-purpose conjunctive filtering algorithm. Secondly, we illustrate the effectiveness of the subscription pruning routing optimization and compare it to the existing covering optimization approach. Finally, we demonstrate the optimization effect of advertisement pruning while maintaining the existing overlapping relationships in the system.

Pruning of indeterminate tomato plants is vital for a profitable yield and it still remains a manual process. There has been research in automated pruning of grapevines, trees, and other plants, but tomato plants have yet to be explored. Wage increases are contributing to the depleting profits of greenhouse tomato farmers. Rises in population are the driving force behind the need for efficient growing techniques. The major contribution of this thesis is a computer vision algorithm for detecting greenhouse tomato pruning points without the use of depth sensors. Given an up-close 2-D image of a tomato stem with the background excluded, the algorithm proposed in this work can detect and mark the tomato suckers.

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