OCLC Online Computer Library Center, Incorporated d/b/a OCLC is an American nonprofit cooperative organization "dedicated to the public purposes of furthering access to the world's information and reducing information costs". It was founded in 1967 as the Ohio College Library Center. OCLC and its member libraries cooperatively produce and maintain WorldCat, the largest online public access catalog in the world. OCLC is funded by the fees that libraries have to pay for its services. OCLC maintains the Dewey Decimal Classification system. OCLC began in 1967, as the Ohio College Library Center, through a collaboration of university presidents, vice presidents, library directors who wanted to create a cooperative computerized network for libraries in the state of Ohio; the group first met on July 5, 1967 on the campus of the Ohio State University to sign the articles of incorporation for the nonprofit organization, hired Frederick G. Kilgour, a former Yale University medical school librarian, to design the shared cataloging system.
Kilgour wished to merge the latest information storage and retrieval system of the time, the computer, with the oldest, the library. The plan was to merge the catalogs of Ohio libraries electronically through a computer network and database to streamline operations, control costs, increase efficiency in library management, bringing libraries together to cooperatively keep track of the world's information in order to best serve researchers and scholars; the first library to do online cataloging through OCLC was the Alden Library at Ohio University on August 26, 1971. This was the first online cataloging by any library worldwide. Membership in OCLC is based on use of services and contribution of data. Between 1967 and 1977, OCLC membership was limited to institutions in Ohio, but in 1978, a new governance structure was established that allowed institutions from other states to join. In 2002, the governance structure was again modified to accommodate participation from outside the United States.
As OCLC expanded services in the United States outside Ohio, it relied on establishing strategic partnerships with "networks", organizations that provided training and marketing services. By 2008, there were 15 independent United States regional service providers. OCLC networks played a key role in OCLC governance, with networks electing delegates to serve on the OCLC Members Council. During 2008, OCLC commissioned two studies to look at distribution channels. In early 2009, OCLC negotiated new contracts with the former networks and opened a centralized support center. OCLC provides bibliographic and full-text information to anyone. OCLC and its member libraries cooperatively produce and maintain WorldCat—the OCLC Online Union Catalog, the largest online public access catalog in the world. WorldCat has holding records from private libraries worldwide; the Open WorldCat program, launched in late 2003, exposed a subset of WorldCat records to Web users via popular Internet search and bookselling sites.
In October 2005, the OCLC technical staff began a wiki project, WikiD, allowing readers to add commentary and structured-field information associated with any WorldCat record. WikiD was phased out; the Online Computer Library Center acquired the trademark and copyrights associated with the Dewey Decimal Classification System when it bought Forest Press in 1988. A browser for books with their Dewey Decimal Classifications was available until July 2013; until August 2009, when it was sold to Backstage Library Works, OCLC owned a preservation microfilm and digitization operation called the OCLC Preservation Service Center, with its principal office in Bethlehem, Pennsylvania. The reference management service QuestionPoint provides libraries with tools to communicate with users; this around-the-clock reference service is provided by a cooperative of participating global libraries. Starting in 1971, OCLC produced catalog cards for members alongside its shared online catalog. OCLC commercially sells software, such as CONTENTdm for managing digital collections.
It offers the bibliographic discovery system WorldCat Discovery, which allows for library patrons to use a single search interface to access an institution's catalog, database subscriptions and more. OCLC has been conducting research for the library community for more than 30 years. In accordance with its mission, OCLC makes its research outcomes known through various publications; these publications, including journal articles, reports and presentations, are available through the organization's website. OCLC Publications – Research articles from various journals including Code4Lib Journal, OCLC Research, Reference & User Services Quarterly, College & Research Libraries News, Art Libraries Journal, National Education Association Newsletter; the most recent publications are displayed first, all archived resources, starting in 1970, are available. Membership Reports – A number of significant reports on topics ranging from virtual reference in libraries to perceptions about library funding. Newsletters – Current and archived newsletters for the library and archive community.
Presentations – Presentations from both guest speakers and OCLC research from conferences and other events. The presentations are organized into five categories: Conference presentations, Dewey presentations, Distinguished Seminar Series, Guest presentations, Research staff
An experiment is a procedure carried out to support, refute, or validate a hypothesis. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a particular factor is manipulated. Experiments vary in goal and scale, but always rely on repeatable procedure and logical analysis of the results. There exists natural experimental studies. A child may carry out basic experiments to understand gravity, while teams of scientists may take years of systematic investigation to advance their understanding of a phenomenon. Experiments and other types of hands-on activities are important to student learning in the science classroom. Experiments can raise test scores and help a student become more engaged and interested in the material they are learning when used over time. Experiments can vary from personal and informal natural comparisons, to controlled. Uses of experiments vary between the natural and human sciences. Experiments include controls, which are designed to minimize the effects of variables other than the single independent variable.
This increases the reliability of the results through a comparison between control measurements and the other measurements. Scientific controls are a part of the scientific method. Ideally, all variables in an experiment are controlled and none are uncontrolled. In such an experiment, if all controls work as expected, it is possible to conclude that the experiment works as intended, that results are due to the effect of the tested variable. In the scientific method, an experiment is an empirical procedure that arbitrates competing models or hypotheses. Researchers use experimentation to test existing theories or new hypotheses to support or disprove them. An experiment tests a hypothesis, an expectation about how a particular process or phenomenon works. However, an experiment may aim to answer a "what-if" question, without a specific expectation about what the experiment reveals, or to confirm prior results. If an experiment is conducted, the results either support or disprove the hypothesis.
According to some philosophies of science, an experiment can never "prove" a hypothesis, it can only add support. On the other hand, an experiment that provides a counterexample can disprove a theory or hypothesis, but a theory can always be salvaged by appropriate ad hoc modifications at the expense of simplicity. An experiment must control the possible confounding factors—any factors that would mar the accuracy or repeatability of the experiment or the ability to interpret the results. Confounding is eliminated through scientific controls and/or, in randomized experiments, through random assignment. In engineering and the physical sciences, experiments are a primary component of the scientific method, they are used to test theories and hypotheses about how physical processes work under particular conditions. Experiments in these fields focus on replication of identical procedures in hopes of producing identical results in each replication. Random assignment is uncommon. In medicine and the social sciences, the prevalence of experimental research varies across disciplines.
When used, experiments follow the form of the clinical trial, where experimental units are randomly assigned to a treatment or control condition where one or more outcomes are assessed. In contrast to norms in the physical sciences, the focus is on the average treatment effect or another test statistic produced by the experiment. A single study does not involve replications of the experiment, but separate studies may be aggregated through systematic review and meta-analysis. There are various differences in experimental practice in each of the branches of science. For example, agricultural research uses randomized experiments, while experimental economics involves experimental tests of theorized human behaviors without relying on random assignment of individuals to treatment and control conditions. One of the first methodical approaches to experiments in the modern sense is visible in the works of the Arab mathematician and scholar Ibn al-Haytham, he conducted his experiments in the field of optics - going back to optical and mathematical problems in the works of Ptolemy - by controlling his experiments due to factors such as self-criticality, reliance on visible results of the experiments as well as a criticality in terms of earlier results.
He counts as one of the first scholars using an inductive-experimental method for achieving results. In his book "Optics" he describes the fundamentally new approach to knowledge and research in an experimental sense: "We should, that is, recommence the inquiry into its principles and premisses, beginning our investigation with an inspection of the things that exist and a survey of the conditions of visible objects. We should distinguish the properties of particulars, gather by induction what pertains to the eye when vision takes place and what is found in the manner of sensation to be uniform, unchanging and not subject to doubt. After which we should ascend in our inquiry and reasonings and orderly, criticizing premisses and exercising caution in regard to conclusions – our aim in all that we make subject to inspect
The reminiscence bump is the tendency for older adults to have increased recollection for events that occurred during their adolescence and early adulthood. It was identified through the study of autobiographical memory and the subsequent plotting of the age of encoding of memories to form the lifespan retrieval curve; the lifespan retrieval curve is a graph that represents the number of autobiographical memories encoded at various ages during the life span. The lifespan retrieval curve contains three different parts. From birth to five years old is a period of childhood amnesia, from 16 to 25 years old is the reminiscence bump and last is a period of forgetting from the end of the reminiscence bump to present time; the reminiscence bump has been observed on the lifespan retrieval curve in multiple studies. The reminiscence bump occurs because memory storage in autobiographical memory is not consistent through time. Rather, memory storage increases during times of changes in the self and in life goals, such as the changes in identity that occur during adolescence.
Researchers have observed the reminiscence bump, the period of increased memory accessibility in participants' lifespan retrieval curves, the bump has been reproduced under a range of study conditions. Adolescence and early adulthood have been described as special times in memory encoding because individuals recall a disproportionate number of autobiographical memories from those periods; the reminiscence bump accounts for this disproportionate number of memories. The reminiscence bump occurs between 10 years of age and 30 years of age and is the period that individuals produce the most memories during free recall tasks. Research suggests that memories are accessible from the reminiscence bump because they are linked to self-identity; the memories found within the reminiscence bump contribute to an individual's life goals, self-theories and beliefs. Additionally, life events that occur during the period of the reminiscence bump, such as graduation, marriage, or the birth of a child, are very novel, making them more memorable.
There are three possible explanations of the reminiscence bump: a cognitive account, a narrative/identity account, a biological/maturational account. The cognitive account suggests that memories are remembered best because they occur during a period of rapid change followed by a period of relative stability. There is an assumed memory advantage for the novel and distinct events, followed by a period of stability; the novel events are subject to greater elaborative cognitive processing leading to better encoding of these memories. Moreover, the period of stability that follows increases the stability of the cues for these memories and increases the chances of recall; the narrative/identity account suggests that the reminiscence bump occurs because a sense of identity develops during adolescence and early adulthood. Research suggests that memories that have more influence and significance to one's self are more rehearsed in defining one's identity, are therefore better remembered in life. Identity formation provides added motivation for using cognitive processes to ensure recall of these memories.
The events from this period are more to be organized into a story or view of oneself, benefits from the advantage of schematic organization in memory. The biological/maturational account suggests that genetic fitness is improved by having many memories that fall within the reminiscence bump. Cognitive capacities are at their optimum from the ages of 10 to 30 and the reminiscence bump may reflect a peak in cognitive performance; this account is therefore sometimes called the cognitive abilities account. Researchers have suggested that the increase of cognitive ability in early adulthood may cause memories during this time period to be more adequately stored; the reminiscence bump is caused by age-related differences in encoding efficiency, which cause more memories to be stored in adolescence and early adulthood. There is one additional theory that explains the occurrence of the reminiscence bump: the life script account. A life script refers to the series of culturally important transitional events that are expected to occur in a certain order at various points during the life span.
During early adulthood one starts to make important decisions and have influencing experiences on his or her identity. The memories during this time period are therefore more remembered because they are what has determined and influenced their life script. A life script has the majority of expected transitional experiences occur during early adulthood, include includes positive experiences such as marriage, the birth of a baby, or buying a house. Events that deviate from the life script are sad and traumatic; these events, such as the death of a child, are not culturally expected and do not show a peak of recall at any specific point during the life span. Life scripts act as a way to structure memory and lead to the expectation that the happiest and the most important life events form the reminiscence bump. Contrary to the recall of happy events, the recall of sad events remains stable across the life span and does not exhibit a bump in recall. Used objects from his environment to cue memories from his life.
Galton created lists of cue-words to stimulate memory recall. He recorded the amount of time required to recall an autobiographical memory related to the cue- word and note the distribution of memories over the life span. Mimicked Galton's technique and had participants recall and date autobiographical memories in response to the cue- words. Participants were encou
Autobiographical memory is a memory system consisting of episodes recollected from an individual's life, based on a combination of episodic and semantic memory. It is thus a type of explicit memory. Conway and Pleydell-Pearce proposed that autobiographical memory is constructed within a self-memory system, a conceptual model composed of an autobiographical knowledge base and the working self; the autobiographical knowledge base contains knowledge of the self, used to provide information on what the self is, what the self was, what the self can be. This information is categorized into three broad areas: lifetime periods, general events, event-specific knowledge. Lifetime periods are composed of general knowledge about a distinguishable and themed time in an individual's life, such as the period you spend at school, or when you entered the workforce. Lifetime periods have a distinctive beginning and ending, but they are fuzzy and overlap. Lifetime periods contain thematic knowledge about the features of that period, such as the activities and locations involved, as well as temporal knowledge about the duration of the period.
The thematic information in these periods can be used to group them together under broader themes, which can reflect personal attitudes or goals. As an example, a lifetime period with the theme of "when I lost my job" could fall under the broader category of either "when everything went downhill for me" or "minor setbacks in my life." General events are more specific than lifetime periods and encompass single representations of repeated events or a sequence of related events. General events group into clusters with a common theme, so that when one memory of a general event is recalled, it cues the recall of other related events in memory; these clusters of memories form around the theme of either achieving or failing to achieve personal goals. Clusters of general events that fall under the category of "first-time" achievements or occasions seem to have a particular vividness, such as the first time kissing a romantic partner, or the first time going to a ball game; these memories of goal-attainment pass on important information about the self, such as how a skill can be acquired, or an individual's success and failure rates for certain tasks.
Event-specific knowledge is vividly detailed information about individual events in the form of visual images and sensory-perceptual features. The high levels of detail in ESK fade quickly, though certain memories for specific events tend to endure longer. Originating events, turning points, anchoring events and analogous events are all event specific memories that will resist memory decay; the sensory-perceptual details held in ESK, though short-lived, are a key component in distinguishing memory for experienced events from imagined events. In the majority of cases, it is found that the more ESK a memory contains, the more the recalled event has been experienced. Unlike lifetime periods and general events, ESK are not organized in their recall. Instead, they tend to simply'pop' into the mind. ESK is thought to be a summary of the content of episodic memories, which are contained in a separate memory system from the autobiographical knowledge base; this way of thinking could explain the rapid loss of event-specific detail, as the links between episodic memory and the autobiographical knowledge base are quickly lost.
These three areas are organised in a hierarchy within the autobiographical knowledge base and together make up the overall life story of an individual. Knowledge stored in lifetime periods contain cues for general events, knowledge at the level of general events calls upon event-specific knowledge; when a cue evenly activates the autobiographical knowledge base hierarchy, all levels of knowledge become available and an autobiographical memory is formed. When the pattern of activation encompasses episodic memory autonoetic consciousness may result. Autonoetic consciousness or recollective experience is the sense of "mental time travel", experienced when recalling autobiographical memories; these recollections consist of a sense of self in the past and some imagery and sensory-perceptual details. Autonoetic consciousness reflects the integration of parts of the autobiographical knowledge base and the working self; the working self referred to as just the'self', is a set of active personal goals or self-images organized into goal hierarchies.
These personal goals and self-images work together to modify cognition and the resulting behaviour so an individual can operate in the world. The working self is similar to working memory: it acts as a central control process, controlling access to the autobiographical knowledge base; the working self manipulates the cues used to activate the knowledge structure of the autobiographical knowledge base and in this way can control both the encoding and recalling of specific autobiographical memories. The relationship between the working self and the autobiographical knowledge base is reciprocal. While the working self can control the accessibility of autobiographical knowledge, the autobiographical knowledge base constrains the goals and self-images of the working self within who the individual is and what they can do. There are four main categories for the types of autobiographical memories: Biographical or Personal: These autobiographical