Information Infrastructures in Distributed Environments: Algorithms for Mobile Networks and Resource Allocation

A distributed system is a collection of computing entities that communicate with each other to solve some problem. Distributed systems impact almost every aspect of daily life (e.g., cellular networks and the Internet); however, it is hard to develop services on top of distributed systems due to the unreliable nature of computing entities and communication. As handheld devices with wireless communication capabilities become increasingly popular, the task of providing services becomes even more challenging since dynamics, such as mobility, may cause the network topology to change frequently. One way to ease this task is to develop collections of information infrastructures which can serve as building blocks to design more complicated services and can be analyzed independently. The first part of the dissertation considers the dining philosophers problem (a generalization of the mutual exclusion problem) in static networks. A solution to the dining philosophers problem can be utilized when there is a need to prevent multiple nodes from accessing some shared resource simultaneously. We present two algorithms that solve the dining philosophers problem. The first algorithm considers an asynchronous message-passing model while the second one considers an asynchronous shared-memory model. Both algorithms are crash fault-tolerant in the sense that a node crash only affects its local neighborhood in the network. We utilize failure detectors (system services that provide some information about crash failures in the system) to achieve such crash fault-tolerance. In addition to crash fault-tolerance, the first algorithm provides fairness in accessing shared resources and the second algorithm tolerates transient failures (unexpected corruptions to the system state). Considering the message-passing model, we also provide a reduction such that given a crash fault-tolerant solution to our dining philosophers problem, we implement the failure detector that we have utilized to solve our dining philosophers problem. This reduction serves as the first step towards identifying the minimum information regarding crash failures that is required to solve the dining philosophers problem at hand. In the second part of this dissertation, we present information infrastructures for mobile ad hoc networks. In particular, we present solutions to the following problems in mobile ad hoc environments: (1) maintaining neighbor knowledge, (2) neighbor detection, and (3) leader election. The solutions to (1) and (3) consider a system with perfectly synchronized clocks while the solution to (2) considers a system with bounded clock drift. Services such as neighbor detection and maintaining neighbor knowledge can serve as a building block for applications that require point-to-point communication. A solution to the leader election problem can be used whenever there is a need for a unique coordinator in the system to perform a special task

Role of Staphylococcal Superantigen in Atopic Dermatitis: Influence on Keratinocytes

Staphylococcus aureus may perform an crucial function in atopic dermatitis (AD), via the secretion of superantigens, including staphylococcal enterotoxins (SE) A or B, and toxic shock syndrome toxin-1 (TSST-1). Dysregulated cytokine production by keratinocytes (KCs) upon exposure to staphylococcal superantigens (SsAgs) may be principally involved in the pathophysiology of AD. We hypothesized that lesional KCs from AD may react differently to SsAgs compared to nonlesional skin or normal skin from nonatopics. We conducted a comparison of HLA-DR or CD1a expression in lesional skin as opposed to that in nonlesional or normal skin by immunohistochemistry (IHC). We also compared, using ELISA, the levels of IL-1α, IL-1β, and TNF-α secreted by cultured KCs from lesional, nonlesional, and normal skin, after the addition of SEA, SEB and TSST-1. IHC revealed that both HLA-DR and CD1a expression increased significantly in the epidermis of lesional skin versus nonlesional or normal skin in quite a similar manner. IL-1α, IL-1β, and TNF-α secretion was also significantly elevated in the cultured KCs from lesional skin after the addition of SsAgs. Our results indicated that KCs from lesional skin appear to react differently to SsAgs and increased proinflammatory cytokine production in response to SsAgs may contribute to the pathogenesis of AD

FEMALE PEASANTS AND THE ALTERNATIVE AGRI-FOOD MOVEMENT IN SOUTH KOREA: AGROECOLOGY AND THE KOREAN WOMEN PEASANT ASSOCIATION MOVEMENT

This paper examines the current state and socio-ecological implications of the alternative agri-food movement organized by the Korean Women Peasant Association (KWPA) in South Korea. In the process of rapid industrial development, South Korean farm sector has suffered from serious environmental problems, depopulation, and poverty. Food production itself has become mostly industrialized using abundant amount of chemical input. This, along with mass consumption system relying on large supermarkets, has led to an unsustainable food system. In this situation, there has been a rise of alternative agri-food movement by the KWPA. We have focused on the influence of agroecology in the KWPA’s activities, which might bring about a more sustainable food system. Under the dominant paradigm of agro-industrialism, farm production inevitably depends on outside resources. This de-contextualizes and disconnects farming from local ecosystems and social relations. Agroecology has emerged in recent years as an alternative paradigm, which can reconnect farming, nature, and society. We have analyzed the KWPA’s programs, such as the indigenous seed preservation movement (ISPM) and Sisters’ Garden Plot (SGP). We have found that agroecology plays an important role in the KWPA’s programs, which involve sharing indigenous farm knowledge; preserving and finding indigenous seeds; and providing seasonal, local, and organic food to the public. These activities have also led to the empowerment of female peasants. These as a whole could be important social resource for a transition to a more sustainable food system

Adenofibroma of Skene's Duct: A Case Report

Skene's glands, also known as paraurethral glands, are homologues of the male prostate, in which painless cystic masses and inflammation due to obstruction have been rarely found and reported. In addition, there have been rare reported cases of adenocarcinoma of Skene's glands. Recently, the authors experienced the first case of adenofibroma arising in Skene's glands of a 62-year-old woman with coital pain. Hereby, we present the case with pathologic and immunohistochemical findings and a short review of literature

Bilateral acromial stress fractures in a patient with a massive rotator cuff tear

Stress fractures of the acromion and scapular spine are well-known complications following reverse total shoulder arthroplasty. However, these fractures in patients with massive rotator cuff tear or cuff tear arthropathy are extremely rare, and the pathogenesis, clinical features, diagnosis, and treatment of these fractures are poorly understood. We report a case of bilateral stress fracture of the posterior angle of the acromion in a patient with massive rotator cuff tear and discuss the pathogenesis, clinical manifestation, and treatment with a review of the literature