• STI Policy Review
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• v.1 no.1
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• pp.93-109
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• 2010

Over the last decade, some Korean enterprises have emerged to become global players in their specialized products. How have they achieved such tremendous technological progress in a short period of time? This paper explores that question by examining the characteristics of technological innovation activities at major Korean enterprises. The paper begins with a brief review of the stages of economic growth and science and technology development in Korea. Then, the existing literature, explaining the Korean innovation model, is analyzed in order to establish a new framework for the Korean innovation model. Specifically, Korean firms have experienced three sequential phases, and thus, the Korean model, at the firm level, can be coined as "path-following," "path-revealing," and "path-creating." Then, the stylized facts in the first phase (path-following) and the second phase (path-revealing) are discussed, in the context of empirical evidence from the areas of memory chips, automobiles, shipbuilding, and steel. In terms of technology development, the Korean model has evolved as "collective learning" in the first phase, "collective recombination" of existing knowledge and technology in the second phase, and is assumed as "collective creativity" in the third phase. Ultimately, all three can be classified as "collective creation". Korean firms now face a transition in the modes of technological innovation in order to efficiently implement the third phase. To achieve remarkable progress again, as they did in the past, and to sustain the growth momentum, Korean firms should challenge new dimensions such as creative technological ideas, distinctive technological capabilities, and unique innovation systems -- all of which connote 'uniqueness'. Finally, some lessons from the Korean technological innovation experience are addressed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.5
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• pp.348-356
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• 2021

Field-effect transistors (FETs) are the key elements of conventional electronics; hence, have drawn a lot of research and commercial interests. In recent years, metal halide perovskite materials have achieved a remarkable efficiency of 29.15% in the field of photovoltaics, and have drawn the scientific community's attention to promote their use in the field of optoelectronics, such as FETs and phototransistors. The MAPbI₃ (methylammonium lead iodide) perovskite TFT has achieved a record hole mobility of 21.41 cm²/V-s in the year 2020. In this review, we will briefly discuss the physical structure of MAPbI₃ perovskite and the essential factors that stimulate these devices, together with the role of defects, the ion migration concept, and the implication of both dielectric and electrode materials on the device's performance.

• Clinical and Experimental Vaccine Research
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• v.13 no.1
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• pp.42-53
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• 2024

Purpose: Conduct a systematic review of case reports and case series regarding the development of acute abdomen following coronavirus disease 2019 (COVID-19) vaccination, to describe the possible association and the clinical and demographic characteristics in detail. Materials and Methods: This study included case report studies and case series that focused on the development of acute abdomen following COVID-19 vaccination. Systematic review studies, literature, letters to the editor, brief comments, and so forth were excluded. PubMed, Scopus, EMBASE, and Web of Science databases were searched until June 15, 2023. The Joanna Briggs Institute tool was used to assess the risk of bias and the quality of the study. Descriptive data were presented as frequency, median, mean, and standard deviation. Results: Seventeen clinical case studies were identified, evaluating 17 patients with acute abdomen associated with COVID-19 vaccination, which included acute appendicitis (n=3), acute pancreatitis (n=9), diverticulitis (n=1), cholecystitis (n=2), and colitis (n=2). The COVID-19 vaccine most commonly linked to acute abdomen was Pfizer-BioNTech (messenger RNA), accounting for 64.71% of cases. Acute abdomen predominantly occurred after the first vaccine dose (52.94%). All patients responded objectively to medical (88.34%) and surgical (11.76%) treatment and were discharged within a few weeks. No cases of death were reported. Conclusion: Acute abdomen is a rare complication of great interest in the medical and surgical practice of COVID-19 vaccination. Our study is based on a small sample of patients; therefore, it is recommended to conduct future observational studies to fully elucidate the underlying mechanisms of this association.

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.5
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• pp.50-59
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• 1992

A critical speed analysis of a pump shaft has been investigated. Among various methods in the shaft critical speed calculation, a transfer matrix method has been examined in this research. After a brief review on the transfer matrix method, a modeling procedure for a continuous structure has been discussed. Then, a critical speed of a multistage pump shaft has been estimated up to several low modes. Throughout an analysis, parametric effects on the bearing stiffness, a degree of the modeling order, and attachmant of the impeller have been investigated. As an application example, a critical speed analysis of a verical pump which has been implemented in domestic electric power plants for cooling water circulation has been conducted in order to provide a safe operation as far as a pump vibration is concerned.

• Interaction and multiscale mechanics
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• v.1 no.4
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• pp.449-465
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• 2008

In this paper a general approach for studying the motion of a cantilever beam interacting with a 2D fluid flow is presented. The fluid is solved by a general purpose commercial computational fluid dynamics (CFD) package (FLUENT 6.2), while the structure is managed by means of a dedicated finite element method solver, coded in FLUENT as a user-defined function (UDF). A weak fluid structure interaction coupling scheme is adopted exchanging information at the end of each time step. An arbitrary cantilever beam can be introduced in the CFD mesh with its wetted boundaries specified; the cantilever can also interact with specified rigid and flexible walls through use of a non-linear contact algorithm. After a brief review of relevant scientific contributions, some test cases and application examples are presented.

• Tuberculosis and Respiratory Diseases
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• v.55 no.1
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• pp.107-112
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• 2003

A congenital cystic adenoid malformation of the lung(CCAM) is characterized by an anomalous fetal development of the terminal respiratory structures, resulting in the adenomatoid proliferation of the bronchiolar elements and cystic formation. CCAM has been detected on the fetus, premature babies and stillborn as well as infants and children. An adult presentation of CCAM is extremely rare. When cystic lesions occur with a repeated infection, an evaluation of the cystic lesions requires a differential diagnosis of CCAM, sequestration, a lung abscess, a pneumatocele and a bronchogenic cyst. The definite treatment of CCAM is the surgical removal of the involved lobe. We report a case of a CCAM in a 24-year-old female with a brief review of the relevant literature.

• Agricultural and Biosystems Engineering
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• v.3 no.1
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• pp.44-54
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• 2002

A brief review of current status in the field of agricultural spray and future research challenges are presented. Researches on the pesticides sprays, pollen sprays, postharvest sprays, and biological control agent sprays among the various applications of agricultural spray were selected and reviewed. In the agrochemical sprays, the techniques to increase the deposition such as electrospray and reduce the drift such as introductions of drift retardants and of mechanical means are reviewed. The introduction of mechanical means includes low drift, air-assisted, air inclusion, shield or shroud assisted and pulse flow nozzles. For flat fan nozzles, the data of breakup length and thickness of liquid sheet are essential to understand the atomization processes and develop the transport model to target In the air-assisted spray technology to reduce drift, further works on the effect of application height on drift and air assistance on droplet size should be followed. In addition, methods for quantifying the included air in the air inclusion techniques are required. The atomization characteristics of biopesticides spray are not being elucidated and the formulations of biopesticides should be taken into account the spray characteristics of existing nozzle and sprayer. A few researches on the droplet size of fallout can be found in the literature. A combined technology with electrostatic method into one of method for the reduction of drift may be an effective strategy for increasing deposition and reducing drift. Only an integrated approach involving all stakeholders such as engineers, chemists, and biologists, etc. can result in improved application of agricultural spray.

• BMB Reports
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• v.48 no.4
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• pp.200-208
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• 2015

The field of redox proteomics focuses to a large extent on analyzing cysteine oxidation in proteins under different experimental conditions and states of diseases. The identification and localization of oxidized cysteines within the cellular milieu is critical for understanding the redox regulation of proteins under physiological and pathophysiological conditions, and it will in turn provide important information that are potentially useful for the development of novel strategies in the treatment and prevention of diseases associated with oxidative stress. Antioxidant enzymes that catalyze oxidation/reduction processes are able to serve as redox biomarkers in various human diseases, and they are key regulators controlling the redox state of functional proteins. Redox regulators with antioxidant properties related to active mediators, cellular organelles, and the surrounding environments are all connected within a network and are involved in diseases related to redox imbalance including cancer, ischemia/reperfusion injury, neurodegenerative diseases, as well as normal aging. In this review, we will briefly look at the selected aspects of oxidative thiol modification in antioxidant enzymes and thiol oxidation in proteins affected by redox control of antioxidant enzymes and their relation to disease. [BMB Reports 2015; 48(4): 200-208]

• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.403-420
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• 2010

Nano and micro structure-based biosensors are promising tool for label-free detection of biomolecular interactions with great accuracy. This review gives a brief survey on nano and micro platforms to sense a variety of analytes such as DNA, proteins and viruses. Among incredible nano and micro structure for bio-analytical applications, the scope of this paper will be limited to micro and nano resonators and nanowire field-effect transistors. Nanomechanical motion of the resonators transducers biological information to readable signals. They are commonly combined with an optical, capacitive or piezo-resistive detection systems. Binding of target molecule to the modified surface of nanowire modulates the current of the nanowire through electrical field-effect. Both detection methods have advantages of label-free, real-time and high sensitive detection. These structures can be extended to fabricate array-type sensors for multiplexed detection and high-throughput analysis. The biosensors based on these structures will be applied to lab-on-a-chip platforms and point-of-care diagnostics. Basic concepts including detection mechanisms and trends in their fields will be covered in this review.

• Journal of Environmental Impact Assessment
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• v.9 no.1
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• pp.25-37
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• 2000

This paper presents a study of hydrological and hydraulic model applications in environmental impact statements which were submitted during recent years in Korea. In many cases (almost 70 %), the hydrological and hydraulic changes were neglected from the impact identification processes, even if the proposed actions would cause significant impacts on those environmental items. In most cases where the hydrological and hydraulic impacts were predicted, simple equations were used as an impact prediction tool. Computer models were used in very few cases(5%). Even in these few cases, models were improperly applied and thus the predicted impacts would not be reliable. The improper applications and the impact neglections are attributed to the fact that there are no available model application guidelines as well as no requirements by the review agency. The effects of mitigation measures were not analyzed in most cases. Again, these can be attributed to no formal guidelines available for impact predictions until now. A brief guideline is presented in this paper. This study suggested that the model application should be required and guided in detail by the review agency. It is also suggested that the hydrological and hydraulic items shoud be integrated with the water quality predictions in future, since the non-point source pollution runoff is based on the hydrologic phenomena and the water quality reactions on the hydraulic nature.