126 research outputs found
Estimating high tech Army recruiting markets
This thesis presents exploratory model-building for identifying and analyzing the recruiting market for highly technical occupations for the Army of the future. The "high-tech" ratings were defined based upon their technical characteristics, qualification rates of the youth labor market, and the Army force structure. Using data from the National Longitudinal Survey of Youth (NLSY), three regression equations were developed tp estimate mental eligibility for high-tech ratings as well as interest in joining the military and actual joining behavior, so that recruiting commands can allocate recruiting resources more accurately and efficiently. These prototypical equations and this method of measuring the recruiting market for high-tech ratings provide a good beginning for estimating the recruiting market for any specific occupation.http://archive.org/details/estimatinghighte00choiCaptain, Republic of Korea ArmyApproved for public release; distribution is unlimited
Direction for Reforming Reward Policy for Veterans in Korea
South Korea had numerous fatalities and wounded soldiers during the Korean War and the Vietnam War, and the country is still losing soldiers to a considerable number of injuries and deaths to accidents caused by perilous conditions for conscripted soldiers. Those highly devotional individuals who sacrificed their lives and well-being for the welfare of their state are the very subjects of the veterans affairs policy. The soldiers of war and public casualties are compensated under the Military Pension Act, the Military Service Law and the Courtesy Law. Putting aside the basic idea, the benefits that the primary subjects (the soldiers of war and public casualties) of the veterans policies receive is far inferior than those civilians receive in compensation for accidents. It is necessary to review the Country Compensation Law, which has excluded soldiers from the Country Compensation Claim Right. And medical care and educational support is essential
The effects of sooting in droplet combustion
The study of the burning of a single droplet is an ideal problem from which to gain fundamental understanding of diffusion flame characteristics. Droplet combustion is a complex physico-chemical process that involves a chemically-reacting two-phase flow with phase changes and yet simple experiments and analysis can be used to attain important insights into the burning rate, flame dynamics, kinetic extinction and disruption processes. It is a subject that has been actively studied for the past 40 years with most of the fundamental experiments being performed under reduced-gravity conditions for direct comparisons with theoretical/computational analyses that invoke spherical symmetry assumptions. In the earlier studies, the effects of sooting on the overall burning characteristics were not considered. However, recent microgravity investigations performed at the NASA-LeRC droptowers (Droplet Combustion Experiment) and others indicate that effects of soot and sootcloud formation may be significant during the lifetime of the droplet and therefore must be included in the analysis
Are Neutral Sentiments Worth Considering When Investigating Online Consumer Reviews? Their Relationship with Review Ratings
Online consumer reviews (OCRs) play an important role for firms to understand consumer satisfaction. Prior research on OCRs has used sentiment analysis to identify and quantify consumers’ subjective impressions in terms of positive and negative sentiments. However, OCRs also contain objective facts about the product or service, which are represented by neutral sentiments. In this study, we argue that it is important to distinguish neutral sentiments from those of positivity and negativity when investigating consumer satisfaction. Through a lens of expectation-confirmation theory, we delineate the roles of subjective information in relation to consumer satisfaction, in the sense that consumer satisfaction is mainly formed by one’s subjective expectations and evaluations, not by objective facts of the product or service. The empirical results obtained from OCRs about hotels demonstrate that consumer satisfaction is significantly higher in positive OCRs than neutral ones, and significant lower in negative OCRs than neutral ones. Furthermore, neutral sentiments drastically improve the explanatory power of empirical models, thereby enhancing our understanding of consumer satisfaction. Academically, this study sheds light on the importance of neutral sentiments. Practically, neutral sentiments, when being separated from the other two sentiment categories, contribute to more accurately reflecting consumer satisfaction
The Effects of Rapid Heating of Soot: Implications When Using Laser-Induced Incandescence for Soot Diagnostics
Recent experimental efforts have exploited the high temporal and spatial resolution of laser-induced incandescence (LII) as both a qualitative and quantitative measure of soot volume fraction. As a relatively new diagnostic technique, issues remain as to appropriate excitation laser intensities and the poential intrusive characteristics of LII. The high temperatures to which the soot is heated may accelerate heterogeneous reactions between the soot and flame gases. Vaporization of soot by high energy pulsed laser light has been theoretically modelled and experimentally observed. Potential physical and/or chemical changes in the laser-heated soot raises the question of how the LII signal depends upon these changes as well as the inferred soot volume fraction. Thus we investigated the effects of high energy pulsed laser light on the soot particles
A Carcinoembryonic Antigen-Secreting Adenocarcinoma Arising in Tailgut Cyst : Clinical Implications of Carcinoembryonic Antigen
Tailgut cysts (TGCs) are rare congenital cysts that occur in the retrorectal or presacral spaces. Although most tailgut cysts have been reported as benign, there have been at least 9 cases associated with malignant change. We report herein on an unusual case of a 40-year-old woman with a carcinoembryonic antigen (CEA)-producing adenocarcinoma arising within a TGC who underwent surgical resection and local radiation therapy. Despite the complete resection, metastatic adenocarcinoma developed five months after surgery. CEA-producing adenocarcinoma from a TGC is extremely rare and only two cases, including this case, have been reported in the English medical literature. Besides CEA, the serum levels of CA 19-9 became markedly elevated in this patient. Given that the serum CEA level decreased to the normal range after complete resection of tumor and that the tumor recurrence was associated with a rebound of the CEA serum level, our case shows that serial measurements of serum CEA can be used for treatment planning and for assessing the patient's treatment response for this rare disease
Is Electroencephalography Useful in Children with Developmental Delays but without Overt Seizures?
Purpose Electroencephalography (EEG) is useful for clarifying the association between cortical activity and cognitive processes in children. We investigated whether EEG abnormalities were correlated with developmental delay/intellectual disability (DD/ID) in the absence of clinical seizures. Methods We retrospectively identified 166 children with DD/ID who underwent EEG at Pusan National University Hospital between January 2011 and December 2021. We compared clinical characteristics and test results between those with normal and those with abnormal EEGs. Additionally, we analyzed EEG abnormalities in relation to neurodevelopmental disorders, specifically autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). Results Of the 166 patients, 39 (23.5%) displayed abnormal EEGs, while 127 (76.5%) had normal EEGs. Of the former, 25 (64.1%) patients exhibited epileptiform discharges, including 22 (56.3%) with focal and three (7.7%) with generalized discharges. Focal discharges most frequently affected the central area (35.9%). Twenty patients (51.3%) exhibited rhythmic slowing patterns. Epilepsy diagnoses were significantly more common among patients with abnormal EEGs (n=8, 20.5%) than among those with normal EEGs (n=9, 7.1%) (P<0.001). Of 22 patients with ASD, five (12.8%) had abnormal EEGs. Of 13 patients with ADHD, five (36.4%) had abnormal EEGs, all with epileptiform discharges. Two patients with ASD and two with ADHD exhibited rhythmic slowing. Abnormal EEG findings were significantly more common among those with genetic abnormalities compared to genetically normal patients (26 vs. 13, P=0.017). Conclusion EEG represents a potential screening tool for children with DD. Abnormal EEG findings are associated with increased epilepsy risk, informing diagnosis and treatment planning
SEALONE (Safety and Efficacy of Coronary Computed Tomography Angiography with Low Dose in Patients Visiting Emergency Room) trial: study protocol for a randomized controlled trial
Objective Chest pain is one of the most common complaints in the emergency department (ED). Cardiac computed tomography angiography (CCTA) is a frequently used tool for the early triage of patients with low- to intermediate-risk acute chest pain. We present a study protocol for a multicenter prospective randomized controlled clinical trial testing the hypothesis that a low-dose CCTA protocol using prospective electrocardiogram (ECG)-triggering and limited-scan range can provide sufficient diagnostic safety for early triage of patients with acute chest pain. Methods The trial will include 681 younger adult (aged 20 to 55) patients visiting EDs of three academic hospitals for acute chest pain or equivalent symptoms who require further evaluation to rule out acute coronary syndrome. Participants will be randomly allocated to either low-dose or conventional CCTA protocol at a 2:1 ratio. The low-dose group will undergo CCTA with prospective ECG-triggering and restricted scan range from sub-carina to heart base. The conventional protocol group will undergo CCTA with retrospective ECG-gating covering the entire chest. Patient disposition is determined based on computed tomography findings and clinical progression and all patients are followed for a month. The primary objective is to prove that the chance of experiencing any hard event within 30 days after a negative low-dose CCTA is less than 1%. The secondary objectives are comparisons of the amount of radiation exposure, ED length of stay and overall cost. Results and Conclusion Our low-dose protocol is readily applicable to current multi-detector computed tomography devices. If this study proves its safety and efficacy, dose-reduction without purchasing of expensive newer devices would be possible
Internet Advertising with Information Congestion
L'attention est une ressource rare. Cette étude examine comment l'attention limitée des utilisateurs affecte le marché de la publicité sur Internet. J'analyse pour celà le marché coréen des moteurs de recherche et présente une estimation structurelle de la demande de bannières publicitaires qui tient compte de l'attention limitée des utilisateurs. Le modèle théorique qui sous-tend cette estimation suppose que l'attention des utilisateurs est distribuée de manière hétérogène.Dans ce cadre, je montre qu'une plateforme en monopole tend à diffuser trop d'annonces et que la probabilité que les messages publicitaires atteignent leur cible depend des caractéristiques des utilisateurs et des sites Web.Un modèle de choix discret à coefficients aléatoires est utilisé pour estimer la fonction de demande des utilisateurs. Les deux fonctions de demande et la fonction de profit des plateformes permettent de déduire le taux de marge. Celui-ci comprend trois composantes: un effet de réseau du côté utilisateur, un effet de congestion et l'indice de Lerner.Les modèles d'estimation sous forme réduite sont discutés en guise d'introduction.Ils semblent révéler l'existence d'un phénomène de congestion de l'information sur le marché des moteurs de recherche coréens.L'estimation structurelle que je met en oeuvre consiste tout d'abord à simuler la probabilité qu'un utilisateur prête attention à un message publicitaire posté sur un site Web. Cela permet, dans un second temps, d'indentifier dans quelle mesure la congestion de l'information affecte la demande de publicité.Le modèle estimé permet de prédire la probabilité qu'un message publicitaire donné soit perçu par les utilisateurs d'un site Web. Cette probabilité varie de 0,19 à 0,58 selon les sites et varie egalement selon le sexe, l'âge et le niveau de l'éducation des utilisateurs. Une augmentation de 1% du nombre d'annonces affichées sur une page Web se traduit par une baisse de 0,06% de la probabilité qu'un message publicitaire soit perçu par les utilisateurs.La demande des usagers estimée révèle que la publicité est une nuisance pour 92.17% des utilisateurs. En estimant la demande de publicité, je conclus que l'externalité liée à l'attention limitée des utilisateurs constitue un déterminant important du taux de marge des plateformes.L'étude enfin montre que le niveau de publicité sur les sites Web est systématiquement en dessous du niveau optimum social, ce qui implique que le pouvoir de marché dont bénéficient les sites conduit à une restriction du nombre de bannières publicitaires qui va au-delà de ce qui serait socialement optimal, compte tenu de l'externalité négative que constitue la congestion de l'information. Cela se traduit par une augmentation du surplus des annonceurs mais par une baisse du surplus social (perte sèche).J'effectue enfin une expérience contrefactuelle sur l'impact des logiciels de blocage de publicité. Cette experience révèle que la generalisation de tels logiciels réduit les niveaux d'annonce, parce que la valorisation des utilisateurs par une plateforme correspond au nombre moyen de messages publicitaires qu'ils perçoivent. Ces resultats soulignent que la prise en compte du phénomène de congestion de l'information est essentielle dans l'estimation des demandes de contenus audiovisuels et d'espace publicitaire.Attention is a scarce resource. This study investigates the problem of the limited consumer's attention span and its impact on Internet advertising markets. For this, I explore Korean search engine market and present a structural model of the demand for the display advertising where the limited attention of website users is considered.The theoretical model assumes that the users' attention is distributed heterogeneously in constructing advertising demand.I show that the monopoly platform would send excessive messages in this setting and that the probability of message process differs by characteristics of users and websites.A random-coefficient discrete choice model is used to formulate the user demand function. Having two demand functions at hand, a markup is derived from the platform's profit function and is shown to have three components: Lerner's index, a network effect from user side, and the congestion effect.The reduced-form estimation models are, then, discussed. These estimations are to explore the market characteristics and to find preliminary evidences of the information congestion in Korean Internet search engine market.For the structural estimation, I simulate the probability that a user pays attention to a message posted on the website. This, in turn allows me to identify the extent to which information congestion affects the advertising demand.The estimated model enables me to predict a probability that a message is seen by a user of one particular website in a given month. The probability ranges from .19 to .58 across websites and it depends on gender, age, and education level of website users. I also find that 1% increase in ad level drops 0.06% of user's message process.I separately estimate the user demand function and find that advertising is a nuisance for 92.17% of users. Using estimates from both demands, I find that the externality from the limited attention is an important determinant of the platform's markup.The study shows that the ad level on a website is systematically below the social optimum level, implying that the website's market power leads to a decrease in quantity beyond what would be socially optimal in view of the negative externality from information congestion.The corresponding deadweight loss and the surplus gain for the society are estimated.I perform a counterfactual experiment on the impact of introducing ad avoidance options on websites. From the experiment, I find that ad levels decrease in the share of ad-avoiders because the platform's valuation on users rises in average attention. These results may stress the importance of users' limited attention in the demand estimation of monopoly media markets
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