• Nuclear Engineering and Technology
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• v.30 no.5
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• pp.462-469
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• 1998

A package to transport high-level radioactive materials is required to withstand normal transport and hypothetical accident conditions pursuant to the IAEA and domestic regulations. The package should maintain the structural safety not to release radioactive material in any condition. The structural safety of the package has been evaluated by tests using proto-type or scaled-down models, however, the method by analysis is gradually utilized due to recent advancement of computers and computer codes. In this paper, to evaluate the structural safety of a radioisotope package of the KAERI, the three dimensional impact analyses under 9m free drop and 1m puncture were performed with an explicit finite-element code, the LS-DYNA3D code. The maximum stress intensity on each part was calculated and the structural safety of the package was evaluated in accordance with the regulations.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.03a
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• pp.145-153
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• 2002

A coastwise chemical tanker sailing at full speed has capsized in calm water and whole turing. In the precious paper, we investigated reasons of the accident by demonstrating the proper correction for the free surface effect of the liquid cargo and the bow-sinkage effect. In this paper, we also carry out model experiments of a transverse pressure under the seawater and an outward heel moment according to the heel angle and rudder angle, on the basis of radius of turning circle, ship's speed and drift angle of model ship occurring in turning. It is also shown that the flooding of seawater onto the deck occurring in turning generated a significant outward heel moment and the vertical distance between the center of gravity of the ship and the renter of lateral water drag.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.1
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• pp.103-118
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• 2018

When collision accident between ships or between ship and offshore platform occurs, a common phenomenon that occurs in structures is the plastic deformation accompanied by a large strain such as fracture. In this study, for the rational design against accidental limit state, the plastic material constants of steel plate which is heated by line heating and steel plate formed by cold bending procedure have been defined through the numerical simulation for the high speed tension test. The usefulness of the material constants included in Cowper-Symonds model and Johnson-Cook model and the assumption that strain rate can be neglected when strain rate is less than the intermediate speed are verified through free drop test as well as comparing with numerical results in several references. This paper ends with describing the future study.

• Journal of Chest Surgery
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• v.14 no.4
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• pp.339-344
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• 1981

Eight patients underwent tracheal resection and reconstruction for tracheostomy and postintubation injuries from 1971 to early 1981. The ages ranged from 12 years to 59 years. The patients had 7-cuff stenosis and one stomal lesion in whom intubated long. Four male and four female patients were treated. Cervical approach was used in one, cervicomediastinal in 3 and transthoracic in four. The longest length of resection extended to 4 cm in whom cervico-upper half mediastinal incision and neck flexion were applied. Techniques for obtaining tension-free anastomosis included cervical flexion or division of the inferior pulmonary ligament and mobilization of the right hilum. Concurrent tracheostomy was not needed in all. There was one death at the end of emergency operation from anesthetic accident. Granulations at the anastomosis line, necessitating bronchoscopy, were noted in two and the lesion did not recurred after removal. No restenosis or other complications occurred during long follow-up.

• Electronics and Telecommunications Trends
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• v.36 no.1
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• pp.22-31
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• 2021

In this thesis, we examine the development status of autonomous mobility services using various artificial intelligence algorithms and propose a solution by combining edge and cloud computing to overcome technical difficulties. A fully autonomous vehicle with enhanced safety and ethics can be implemented using the proposed solution. In addition, for the future of 2035, we present a new concept that enables two- and three-dimensional movement via cooperation between ecofriendly, low-noise, and modular fully autonomous vehicles. The zero-error autonomous driving system will safely and conveniently transport people, goods, and services without time and space constraints and contribute to the autonomous mobility services that are free from movement in connection with various mobility.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.235-239
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• 2016

The capsizing speed of an unstable vessel with a lost restoring moment can be understood as a unique response to an accident situation, and is naturally affected by such parameters as moment of inertia, metacentric height, and transverse damping coefficient of the hull in the case of free roll motion. Additionally, it is supposed that the analysis of capsize accidents can be further simplified when a vessel's leaning velocity is shown to be quite low. Therefore, capsize accidents with low leaning speeds are desirably categorized in view of rescuing strategies, as opposed to fast capsize accidents, since the attitude of the declining hull can be properly estimated, which allows rescuers to have more time for helping accident cases. This study focuses on deriving some analytical equations based on the roll decay ratio parameter, which describes how a hull under a low-speed capsize is related to the situational hull characteristics. The suggested equations are applied to a particular ship to disclose the analytical responses from the model ship. It was confirmed that the results show the general characteristics of slow capsizing ships.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.101-108
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• 2018

This study was carried out to obtain baseline data on the causes of industrial accidents and their prevention by investigating structural models between the Shipyard workers' egogram ego-states (CP: Critical Parent, NP: Nurturing Parent, A: Adult, FC: Free Child, AC: Adapted Child), safe and unsafe behaviors, and industrial accidents (frequency/severity). In order to achieve this goal, 378 workers from 3 locations of major corporations in Geojedo Island and Ulsan took a questionnaire, which was then analyzed with a structural equation model using the SPSS 23.0 and AMOS 24 statistics package, and the main results of the study are as follows. First, NP and A's ego-states had a positive influence on safe behavior, AC's ego-state had a negative influence on safe behavior, and A's ego-state had the largest influence on safe behavior. Second, CP and AC's ego-states had a positive influence on unsafe behavior, and A's ego-state had a negative influence on unsafe behavior. AC's ego-state had the largest influence on unsafe behavior. Third, safe behavior did not have a significant influence on industrial accidents. However, unsafe behavior had a positive influence on industrial accident frequency and industrial accident severity, both sub-factors of industrial accidents. This study, despite its limitations, such as sampling limitations, has the following significance. First, this study verified that ego-state, a psychological characteristic, is an important factor for predicting unsafe behavior that induces industrial accidents. Second, in order to reduce industrial accidents, there is a need to stimulate the A ego-states, and promote continuous safety management and safety education to neutralize the AC ego-state. Third, previous studies were limited in the area of practical methods for reducing unsafe behaviors, but this study presents practical methods for reducing unsafe behaviors by verifying the structural relationship between safe/unsafe behaviors and industrial accidents by selecting ego-gram ego-states, variable personality theory, as an independent variable.

• Journal of Korean Foot and Ankle Society
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• v.1 no.1
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• pp.59-64
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• 1997

The aims of free tissue transplantation to the injured foot are to cover the exposed blood vessels, nerves, muscles, tendons and bones, to clear up infection, to lessen the morbidity, to shorten the hospitalization, and to prepare for further surgical procedures when no local or transpositioning flaps are available. Authors have carried out free flap transplantation in 13 cases of crushing injury, osteomyelitis and electrical burn in the foot at Chonbuk National University Hospital from June 1992 through May 1996. The results were as follows : 1. 9 cases of 13 (69%) were sustained from the traffic accident. 2. The dorsalis pedis free flap transplantation has been performed most frequently in 5 cases (38.5%), followed gracilis muscle flap in 4 cases(30.7%), rectus abdominis muscle flap in 2 cases(15.4%), latissimus dorsi muscle flap and upper arm flap in 1 each. 3. 6 muscle flaps were covered with split thickness skin graft 20 days after microsurgical anastomosis. 4. All of 13 cases were survived after microsurgical procedure and showed excellent coverage in the foot.

• Archives of Reconstructive Microsurgery
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• v.18 no.2
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• pp.62-66
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• 2009

Purpose: Despite the free tissue transfer using microsurgical technique being the current trend of soft tissue reconstruction of the hand, the pedicled groin flap has the advantage to provide coverage for the mangled hand without necessitating the use of a damaged arterial system and also providing the benefit of saving the arterial system for later free tissue transfer. This report presents the author's experience using pedicled groin flap in four cases of mangled hands with massive bone and soft tissue defects requiring later thumb reconstruction with the free wrap around flap. Materials and methods: The patients' age ranged from 30 to 51 years; three patients were male and one was female. The causes of mangled hand included two machinery crush injuries, one laboratory explosion and one motor vehicle accident. While evaluating the post-operative results, factors like flap survival, complications, stability in opposition, pinch power and 2 point discrimination were taken into account. Results: All massive soft tissue defects of the hands were completely covered with pedicled groin flap successfully. The reconstructed thumb using free wrap around flap did not have any limitation in opposition. There was no occurrence of post-operative infection and all the flaps survived completely. The average pinch power was 70% of the contralateral intact thumb and average 2 point discrimination was 10 mm. Conclusion: The pedicled groin flap for the reconstruction of the massive soft tissue defects of the hand with subsequent reconstruction of the thumb with a wrap around flap is a very useful procedure. The combined use of pedicled groin flap and wrap around flap allows adequate coverage of sizable soft tissue defects and functional thumb opposition in cases of reconstruction of the mangled hands.

• Nuclear Engineering and Technology
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• v.39 no.5
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• pp.603-616
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• 2007

Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be! It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where $9*10^{-4}$ initial free heavy metal fraction was typical for early AVR carbide fuel and $3*10^{-4}$ initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/ traditional and new materials, manufacturing technologies/ quality control quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with $700-750^{\circ}C$ helium coolant gas exit, for gas turbine applications at $850-900^{\circ}C$ and for process heat/hydrogen generation applications with $950^{\circ}C$ outlet temperatures. There is a clear set of standards for modem high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a $500{\mu}m$ diameter $UO_2$ kernel of 10% enrichment is surrounded by a $100{\mu}m$ thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of $35{\mu}m$ thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum $1600^{\circ}C$ afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modem coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond $1600^{\circ}C$ for a short period of time. This work should proceed at both national and international level.