Effects of Prevalence Expectation on Visual Search Behaviour

Effects of Prevalence Expectation on Visual Search Behaviour Page | 1 Introduction The objective of this research is to investigate the effects of prevalence expectation on visual search behaviour and cognitive function in radio-diagnosis of the adult chest radiograph and its impact upon medical expert witness testimony in malpractice litigation. Research into radiological error has consistently demonstrated disparity in radiological performance. Most studies of radiology error report significant rates of intra and inter observer variability. The pertinent question is why do radiologists make mistakes? â€Å"Conventionally, radiologists produce diagnoses on the basis of a combination of their training, experience, and individual judgment. Radiologists perceive and recognise image patterns and associate or infer a diagnosis consistent with those patterns.† [1] Accurate results depend upon the radiologist’s ability to recognise a lesion, ignore irrelevant details, and retrieve pertinent memories in order to accurately interpret an image. The radiologists primary task is to accurately identify a range of anatomical structures and pathological findings on medical images. The diagnostic process in radiology is not well understood. Basically, radiologists perceive and recognise image patterns and then associate or infer a diagnosis consistent with such patterns. Appearances on a radiograph are silhouettes of normal and abnormal anatomy. Each shadow represents a projection of layers of detail on a two dimensional surface from a three-dimensional object. The successful detect ion of the target and the time required to seek it out depends upon a number of external factors Much information needs to be processed by the radiologist during the interpretation of such shadows. The disease pattern, The clinical and demographic information relating to the patient The differential diagnoses pertaining to such a pattern. The experience of the radiologist A general aspect of everyday life is looking for a particular target amongst an assortment of other (distracting) items. Visual Search is one task that is performed routinely from radiological diagnosis to finding a definitive research text in a library. Visual search is an essential element in the cognitive process and is the interaction between the visual system, its target and the reader’s subsequent decision. Each experiment was conducted in a controlled laboratory environment, but were designed to simulate, as near as possible, the clinical arena. Expectation is explored by manipulating the information given to radiologists between general clinical information and very specific clinical information, thereby encouraging each radiologist to formulate an individual expectation of abnormal prevalence in the images presented to them. We then measured any subsequent change in behaviour as the subjects’ biases shifted. It was hypothesised thata radiologist would vary their decisions at the cost of more or less false alarms. This is termed criterion shift. The amount by which a radiologist considers false alarms to achieve a higher rate of detection is termed the bias. Bias represents an approach to lessen the consequences of a missed target. What is visual search? In a visual search task, subjects look for a target item among a number of distracting items. [1] After breaking down an image into its distinct components, the visual system directs attention to unusual areas for further analysis. This act of looking for and selecting an anomalous feature on a radiographic image is termed visual search, and is the task performed by radiologists daily. At a very basic level, there are generally considered two types of visual search termed pre-attentive and attentive. A great deal of research has been conducted regarding the differences between these two types of visual search and the factors that affect performance during each [2, 3]. Pre-attentive search has been given a number of labels including efficient search, parallel search, easy or effortless search [1] and automatic detection [4]. In this type of search, the targets are anticipated to contain features which are processed pre-attentively [5], basically drawing attention to themselves. In this type of search, the target appears immediately to the observer, requiring little search effort. For example when searching for the letter X on a page of letter Os or for a red target in a mass of blue targets. Attentive search also referred to as inefficient search [1] serial search [4] and controlled search [2] refers to a complicated search in which attention must be given to targets much less obvious. These components are influenced respectively by the characteristics of the environment (e.g., saliency of targets and distracters) and learned search strategies. The distinction between these two types of search is consistent with the view that search is driven by both bottom up and top down processes [6] wherein bottom up processes drive attention due to salient features in an environment or target features and top down processes drive attention through the function of search strategies such as the direction of attention to locations of high priority. Experienced radiologists develop a mental global impression of a standard radiograph [7, 8] sometimes called a target template [9] and in some instances use pre-attentive search as the abnormality is almost instantaneously visible. Conversel y they may use the second approach in more difficult cases. Recognising how these factors influence target detection helps to understand real-world search tasks and cognitive psychology. Together, the results can help to show how different influences affect visual search in the performance of real-life search tasks as in medical radiology, and airport baggage security. Fiore et al [10]) define threat detection in an airport screening task as the ability to rapidly recognise targets in the environment and interpret the meaning and importance of these cues. Nodine et al [11] break the radiological interpretation task down into three elements, describing the task as consisting of a search for, the recognition of an abnormality and the decision made regarding the abnormality. Many occupations depend on the speedy and effective execution of a visual search. Surf life savers in Australia are trained to search the ocean for rips, sharks and for swimmers in difficulty. Diamond cutters need to be able to evaluate the cutting potential of a rough diamond and need to be able to look at a diamond crystal and determine whether it will yield a large enough gemstone to make a profit.The quality and price will vary greatly based on the cut quality [12]. Airport baggage security screeners are trained using Threat Image Projection (TIP) technology to detect potential threat items within an X-ray image that may contain harmless clutter. There are various features which might hamper a successful visual search, including item superimposition, different viewpoints, rotation of the item and general image complexity. A number of other demands may also influence search, including psychosocial pressure (a busy airport might provoke a too rapid search), expectation (a threat it em is a rare occurrence), boredom and the number of different targets added to the list of dangerous or suspicious items. Errors in these areas are potentially life-threatening, expensive or both. In the medical arena, diagnosis in cytology and radiology are two areas that are dependent upon visual search. Clinical understanding and proficiency in visual pattern recognition serve as the basis for diagnosis by radiologists and pathologists [13]. Error in Radiology Imaging departments must offer a top quality radiological service with as little risk to the patient as is possible. It is therefore incumbent upon radiology department to address any problematic areas and try to reduce the causes of error. The accuracy of the radiological report is one element of the patient’s care. In radio-diagnosis, errors are either of perception or cognition [14]. Perceptual errors occur when targets (tumours, infection) are not visualised. A cognitive error occurs when an abnormality is seen but the radiologist draws the wrong conclusions due to unsound diagnostic reasoning. Diagnostic errors are classified as either false positive (FP) or false negative (FN). A false positive decision is due to the interpretation of a presumed target as pathological when it is in fact normal. A false-negative is an abnormality that is present but is not perceived. FN errors errors are five times more likely than FP errors [15], whilst perceptual errors are four times more frequent than decision making errors [14]. Radio-diagnosis not an exact science. Approximately 4% of Radiological interpretations contain errors, fortunately, most of these errors are clinically insignificant, or if serious errors are found, they are promptly corrected causing no harm to patients [16]. Identifying and locating items can be challenging especially when one is uncertain of where, or even what, to look for. Difficulties are more likely to occur when observers must locate the target’s position rather than simply detect the target’s presence [17]. Numerous studies have been conducted to understand error in radio-diagnosis. This issue has been recognised for a number of years. In the 1940s, Garland [18] found that 10-20% of chest radiographs of patients with suspected tuberculosis (TB) were read differently by different observers and a study by Quekel et al [19] observed that 19% of lung cancers presenting as a nodule on chest radiographs were missed. Another study [20] identified major diagnostic variation between three experienced radiologists interpreting medical images of patients in an emergency department. In this study the level of diagnostic agreement between the radiologists varied according to the anatomical area examined. Levels of agreement were abdomen (51%), chest (61%) and musculoskeletal (74%). There are a number of influences that affect the perception and diagnosis of chest lesions. Of these influences, prevalence expectation has had very little study. Target prevalence and prevalence expectation Prevalence expectation or bias occurs when expectations about an outcome influences a subject’s behaviour. In radiology this can be a factor during diagnosis. For statistical reasons, laboratory studies of visual search in typically include targets on 50% of all trials and participants often recognise that any given trial has an equal chance of having a target or not. However, real-life searches are seldom so balanced. In airport security, baggage screeners view numerous x-ray images of suitcases, but the incidence of a dangerous item happens infrequently. Consequently, one issue in visual search is exploring how a difference in target prevalence modifies searcher expectation and subsequent detection performance. This issue has been raised in multiple domains, including vigilance studies, radio-diagnostic perception, and cognitive psychology. In routine radiological examinations, the occurrence of abnormalities is generally low. This frequency fluctuates depending on the demographics of the population and the anatomical area being examined. However, in all cases, a mis-diagnosis might result in serious consequences. Research within radiology has therefore attempted to show whether low target prevalence is responsible for diagnostic error. Whilst a number of studies, within the medical and non-medical domains, have investigated whether the number of targets present (prevalence) can affect performance. [21, 22, 23, 24], there has been almost no research undertaken regarding the effect of prevalence expectation.

Cookies as Spyware Essay

This paper addresses Cookies as Spyware. The option chosen was to analyze the issues associated with cookies being used as spyware. Are cookies pieces of malicious, benign, or innocent software? The next paragraphs of this paper will discuss the various uses of cookies. And, then, the paper will conclude with my opinion about cookies based upon my research findings. Since web browsing uses a stateless connection, cookies are used to maintain the state of a browsing session. Cookies are small data files that are produced by a web server that are stored on your computer. Cookies allow a personalized web browsing experience because of the identifying information that they store within them (such as login information, passwords, web pages visited, and/or items placed in a shopping cart). There are different types of cookies that are created for specific purposes. They include session, persistent, first-party, and third-party cookies. Session cookies are used to store information related to a particular visit during one session. Persistent cookies are used to store information permanently on your hard drive about your interactions and/or preferences with a certain web site. First-party cookies are used by the specific site that created them while their website is being visited, whereas third-party cookies are not created by the website that is being visited. Third-party cookies are created by another website besides the website being visited such as a banner advertisement on the web page that is being visited. (â€Å"Encyclopedia,†) While most cookies appear to be used solely for the purpose of enhancing the user’s web browsing experience, cookies can be used for other purposes including adware or spyware if they contain active code. Adware is used to automatically download or display advertisements on a person’s computer. Spyware is technology used to gather information about a person or organization without their consent or knowledge and relay that information back to advertisers or other interested parties. (â€Å"Information security magazine,† 2008) Technology has evolved to the point where cookies can or have been abused, so they are associated with some security risks. The risks associated with cookies are hijacking (session hijacking), inaccurate identification (due to multiple user accounts or different browsers being used on a single PC), poisoning or stealing (cookie manipulation), and lack of expiration or artificially long expiration periods (allowing cookies to remain when they are no longer needed can allow the cookies to be stolen or attacked). (â€Å"Are all cookies,† 2010) All of these security risks can be used to gain access to or steal personal information from a user or their computer. In conclusion, from the research articles reviewed, it is my opinion that cookies are both beneficial and potentially harmful if used improperly. Cookies can be used safely to enjoy their beneficial purposes for web browsing by following some simple rules. Routinely find and delete unnecessary cookies by navigating to the path on your hard drive where your cookies are stored (C:Documents and Settings[username]Cookies). There really isn’t much danger in deleting these files since new cookies are automatically downloaded the next time you visit the site anyway. Also, check to make sure that your browser settings are only allowing first-party cookies (restrict third-party cookies). Another important thing is to install antivirus software (such as Symantec Endpoint Protection, Sophos, McAfee, or any other reputable vendor) and keep your antivirus software updated properly. Perform regular scans on your hard drive and all attached peripherals to prevent infections. Keep operating system patches updated to prevent anyone from hacking your system because of a known vulnerability. Web browsing would be much less personalized if we completely denied ourselves the privileges associated with cookies.

How Do I See Myself 10 Years from Now?

The way I see myself ten years ahead of now is not something I often think about. To tell you the truth, it scares me a little to know that in one short decade I will be twenty six years old, and that my years of youth are coming to an end. One thing I’m certain of, is that if God gives me the opportunity to get to that age, I will make the most of my years and put all of my effort to become a successful, happy woman. Contemplating on the future doesn’t always come easy since no one really knows if it will ever go the way we think it would.As for me, I envision myself as a happy and most probably, simple individual who has finished most of the plans he has made and set as his life was slowly expended on each day that passed by. These plans would not only involve the actual completion of a series of courses I would really love to graduate from, namely, my current course, Medical Technology. And of course to become also a Registered one. At that age, I am already a full p ledge RMT. Working on a very nice hospital which pays relatively huge sums of money for some meager job I have to accomplish.I will also save my money. I will also travel to Paris with my family. I will let my parents feel and enjoy life through buying them plane tickets and go around the world. I will also help my relatives who ask helps from me. I will work hard so that I can buy anything I want. And experience the things I wanted to do when I was still a child. I will also help and support my younger brother in his studies. I wanted also to continue what I've started. What I'm trying to say is I will go and study at Medicine School. Because my parent want me to become a Doctor.I really wanted also to become one because, as what I mention earlier I want to earned huge sums of money. I want also to help people who doesn't afford to go to hospital. I want also to make my parents proud. At the age of 28 or 29, this is already the right time to experience going out with someone else. I mean it's boyfriend time. Hahaha! It's time to experience how to be love and how to love by special someone. So, I will do all my best to pursue all my dreams. I will follow and listen to my parents. I will also ask the help and guidance of the Lord.

Ancient Egyptian Scarab, Commemorative Scarab And Scarab...

In this paper I will be talking about the Ancient Egyptian Scarab, and it’s significants to Egypt. In great detail, this paper will explore the different scarabs such as the heart scarab, commemorative scarab and scarab amulet. In addition, it will explain if dating scarab is easy or complicated to do. To conclude the paper, I will be comparing an object in today’s culture to the Ancient Egyptian scarab. A scarab is â€Å"an artistic depiction of the indigenous Egyptian dung beetle† according to Kathlyn Cooney. The dung beetle is an insect that rolls balls full of dungs, which is where it lays eggs. The Egyptians linked the beetle to the reproductive behavior of mythological cycles of solar death and rebirth. In addition, the Egyptians used the scarab as a symbol of the sun being pushed across the sky and the sun god can create rebirth. There are many types of scarabs found such as the heart scarab, commemorative scarab and scarab amulet. The first type of scarab, which is the best-known scarab, is the heart scarab. The heart scarab dates back to the 17th Dynasty and it has been described as a large amulet made of green stone, and has inscribed Chapter 30B from the Book of the Dead. The scarab would be placed on top of the mummy in order to control the conscious and memory of the deceit person in justice. A scarab similar to the heart scarab would be the so-called winged scar ab because they are similar in form and size, but lacks the inscription on the underside. The