• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.4
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• pp.36-42
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• 2018

Although continuous passenger injuries and physical damages are repeated due to the unexpected aviation turbulence encountered during operations, there is still exist the limitation for preventing recurrence of similar events because the lack of real-time information and delay in technological developments regarding various operating conditions and variable weather phenomena. The purpose of this study is to compare and analyze the meteorological data of the aviation turbulence occurred and actual flight data extracted from the Quick Access Recorder(QAR) to provide some precursors that the pilot can identify aviation turbulence early by referring thru the flight instrumentation indications. The case applied for this study was recent event, a scheduled flight from Incheon Airport, Korea to Narita Airport, Japan that suddenly encountered turbulence at an altitude of approximately 14,000 feet during approach. According to the Korea Meteorological Administration(KMA)'s Regional Data Assessment and Prediction System(RDAPS) data, it was observed that the strong amount of vorticity in the rear area of jet stream, which existed near Mount Fuji at that time. The QAR data analysis shows significant changes in the aircraft's parameters such as Pitch and Roll angle, Static Air Temperature(SAT), and wind speed and direction in tens of seconds to minutes before encounter the turbulence. If the accumulate reliability of the data in addition and verification of various parameters with continuous analysis of additional cases, it can be the precursors for the pilot's effective and pre-emptive action and conservative prevention measures against aviation turbulence to reduce subsequent passenger injuries in the aviation operations.

• English & American cultural studies
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• v.9 no.1
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• pp.185-219
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• 2009

This article aims to illuminate the comic characters and their humor in Dickens's novel David Copperfield in Bakhtinian point, and to clarify what the humorous characteristics are, and how they contribute to his reinforcement of socially critical messages in this novel. So far this novel has been called the only one of Dickens's comic novels, even though it includes lots of social critical meanings. But it is true that Dickensian critics couldn't make sure of the clear reasons why it is both very interesting and critical. Furthermore, it is also true that this novel has been criticized as a clumsy one in the realistic, psycho-analytic, dramatic angle. This approach to Dickensian comic characters through Bakhtinian fool, clown, and rogue concepts here could make up for or correct such criticisms, and reevaluate Dickens's humor and social criticisms in the context of general public culture. Bakhtin believes oppression by social ideologies prevent us from having good mutual relationships and divides our society. He thinks laughter liberates us from such oppression and restores our good relationships. As he applied his concepts based on the laughter of Middle Ages to Rabelais's novels, and examined what the authentically liberating power in Rabelais's laughter is, this article could clarify the liberating power of laughter by Dickens's comic characters, such as Mr and Mrs Micawber, Dick, Miss Betsey Trotwood and Miss Mowcher. In this novel, they often lead comic happenings, and such happenings are very similar to carnival-amusements including burning the dummy of the czar who has oppressed his or her citizenry. Especially, Dickens's comic characters's social criticisms, in the case of this novel, contain many complaints of social marginers, even though he has been labelled as being conservative politically. They always criticize the ideological absurdities in their society through the humorous words and behaviors in their comic happenings, like those of a carnival fool or clown in his or her amusements. This shows Dickens achieves both laughter and social criticism in David Copperfield by using Rabelaisian characterization-devices based on his general public culture. Like Bakhtin and Rabelais, Dickens seems to have believed that when we all truly liberate ourselves from the oppression of social ideologies, we can have desirable relationships between ourselves, and also solve social problems positively.

• Journal of English Language & Literature
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• v.57 no.4
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• pp.625-649
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• 2011

Even though "An Outpost of Progress" and Heart of Darkness were based upon Joseph Conrad the sailor's same experience in Congo Free State, their narrative strategies are quite different. The realistic representation of "An Outpost of Progress," with which Conrad was not satisfied at all, was converted into the modernistic narrative strategy of Heart of Darkness so that the sympathetic power of the story should be improved. The conservative value system of realism is expressed by the omniscient author in "An Outpost of Progress," whereas the frame narrator of Heart of Darkness is proved to be an unreliable one whose norms and behavior are not in accordance with the implied author. The glorious history of the British Empire, which was proudly presented by the frame narrator at the beginning of Heart of Darkness, was strongly opposed by Marlow, another narrator, who said that the British Empire had been "one of the dark places of the earth" when ruled by the Roman Empire. The feeling of the frame narrator was uneasily changed into the gloomy mood when he described the Thames as the flow which "seemed to lead into the heart of an immense darkness" at the end of Heart of Darkness. Similar to the straightforward narrative strategy of representation in "An Outpost of Progress," the realistic approach of Part I in Heart of Darkness is considered by Conrad as insufficient to reveal the darkest truth of imperialism, which was declared by Kurtz as "The Horror! The Horror!" Thus Conrad uses the Chinese-box structure, in which Kurtz' episode is enveloped by Marlow's tale which is enclosed by the frame narrator's story, in order to penetrate into the mind of ordinary readers in the novelist's age of New Colonialism, while attacking the ideology itself of imperialism instead of critisizing its inefficiency and individualism.

• Tribology and Lubricants
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• v.37 no.3
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• pp.99-105
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• 2021

In this study, for a high-pressure turbine (HPT) of 800 MW class supercritical thermal-power plant, considering aerodynamic cross-coupling, we performed a rotordynamic logarithmic decrement (LogDec) stability analysis with various tilting pad journal bearing (TPJB) designs, which several steam turbine OEMs (original equipment manufacturers) currently apply in their supercritical and ultra-supercritical HPTs. We considered the following TPJB designs: 6-Pad load on pad (LOP)/load between pad (LBP), 5-Pad LOP/LBP, Hybrid 3-Pad LOP (lower 3-Pad tilting and upper 1-Pad fixed), and 5-Pad LBPs with the design variables of offset and preload. We used the API Level-I method for a LogDec stability analysis. Following results are summarized only in a standpoint of LogDec stability. The Hybrid 3-Pad LOP TPJBs most excellently outperform all the other TPJBs over nearly a full range of cross-coupled stiffness. In a high range of cross-coupled stiffness, both the 6-Pad LOP and 5-Pad LOP TPJBs may be recommended as a practical conservative bearing design approach for enhancing a rotordynamic stability of the HPT. As expected, in a high range of cross-coupled stiffness, the 6-Pad LBP TPJBs exhibit a better performance than the 5-Pad LBP TPJBs. However, contrary to one's expectation, notably, the 5-Pad LOP TPJBs exhibit a slightly better performance than the 6-Pad LOP TPJBs. Furthermore, we do not recommend any TPJB design efforts of either increasing a pad offset from 0.5 or a pad preload from 0 for the HPT in a standpoint of stability.

• The Journal of Advanced Prosthodontics
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• v.13 no.6
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• pp.351-360
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• 2021

PURPOSE. The aim of this study was to evaluate the efficiency of occlusal and interproximal adjustments of single implant crowns (SIC), comparing a digital cast-free approach (CF) and a protocol using 3D printed casts (PC). MATERIALS AND METHODS. A titanium implant was inserted at position of lower right first molar in a typodont. The implant position was scanned using an intraoral scanner and SICs were fabricated accordingly. Ten crowns (CF; n = 10) were subject to a digital cast-free workflow without any labside occlusal and interproximal modifications. Ten other identical crowns (PC) were adjusted to 3D printed casts before delivery. All crowns were then adapted to the testing model, simulating chair-side adjustments during clinical placement. Adjustment time, quantity of adjustments, and contact relationship were assessed. Data were analyzed using SPSS software (P < .05). RESULTS. Median and interquartile range (IQR) of clinical adjustment time was 02:44 (IQR 00:45) minutes in group CF and 01:46 (IQR 00:21) minutes in group PC. Laboratory and clinical adjustment time in group PC was 04:25 (IQR 00:59) minutes in total. Mean and standard deviation (±SD) of root mean squared error (RMSE) of quantity of clinical adjustments was 45 ± 7 ㎛ in group CF and 34 ± 6 ㎛ in group PC. RMSE of total adjustments was 61 ± 11 ㎛ in group PC. Quality of occlusal contacts was better in group CF. CONCLUSION. Time effort for clinical adjustments was higher in the cast-free protocol, whereas quantity of modifications was lower, and the occlusal contact relationship was found more favourable.

• Structural Monitoring and Maintenance
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• v.8 no.4
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• pp.345-360
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• 2021

This paper presents an analytical approach to calculate the buckling load of the cylindrical ring structures subjected to both hydrostatic and hydrodynamic pressures. Based on the conservative law of energy and Timoshenko beam theory, a theoretical formula, which can be used to evaluate the critical pressure of buckling, is first derived for the simplified cylindrical ring structures. It is assumed that the hydrodynamic pressure can be treated as an equivalent hydrostatic pressure as a cosine function along the perimeter while the thickness ratio is limited to 0.2. Note that this paper limits the deformed shape of the cylindrical ring structures to an elliptical shape. The proposed analytical solutions are then compared with the numerical simulations. The critical pressure is evaluated in this study considering two possible failure modes: ultimate failure and buckling failure. The results show that the proposed analytical solutions can correctly predict the critical pressure for both failure modes. However, it is not recommended to be used when the hydrostatic pressure is low or medium (less than 80% of the critical pressure) as the analytical solutions underestimate the critical pressure especially when the ultimate failure mode occurs. This implies that the proposed solutions can still be used properly when the subsea vehicles are located in the deep parts of the ocean where the hydrostatic pressure is high. The finding will further help improve the geometric design of subsea vehicles against both hydrostatic and hydrodynamic pressures to enhance its strength and stability when it moves underwater. It will also help to control the speed of the subsea vehicles especially they move close to the sea bottom to prevent a catastrophic failure.

• Clinics in Shoulder and Elbow
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• v.24 no.4
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• pp.209-214
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• 2021

Background: The treatment for acromioclavicular joint injuries (ACJI) ranges from a conservative approach to extensive surgical reconstruction, and the decision on how to manage these injuries depends on the grade of acromioclavicular (AC) joint separation, resources, and skill availability. After a thorough review of the literature, the researchers adopted a simple cost-effective technique of AC joint reconstruction for acute ACJI requiring surgery. Methods: This was a prospective single-center study conducted between April 2017 and April 2018. For patients with acute ACJI more than Rockwood grade 3, the researchers performed open coracoclavicular ligament reconstruction using synthetic sutures along with an Endobutton and a figure of 8 button plate. This was followed by AC ligament repair augmenting it with temporary percutaneous AC K-wires. Clinical outcomes were evaluated using the Constant Murley shoulder score. Results: Seventeen patients underwent surgery. The immediate postoperative radiograph showed an anatomical reduction of the AC joint dislocation in all patients. During follow-up, one patient developed subluxation but was asymptomatic. The mean follow-up period was 30 months (range, 24-35 months). The mean Constant score at 24 months was 95. No AC joint degeneration was noted in follow-up X-rays. The follow-up X-rays showed significant infra-clavicular calcification in 11 of the 17 patients, which was an evidence of a healed coracoclavicular ligament post-surgery. Conclusions: This study presents a simple cost-effective technique with a short learning curve for anatomic reconstruction of acute ACJI. The preliminary results have been very encouraging.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.87-99
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• 2023

Ground excavation inevitably causes ground displacement of adjacent ground, and structures and facilities exposed to ground displacement may suffer various damages. Therefore, in order to minimize the damage and damage to adjacent structures and facilities caused by excavation, ground displacement (settlement and horizontal displacement) in the adjacent ground caused by excavation must first be predicted. There is many ground displacement information induced by general braced cut excavation, but the information is not enough for circular shaft excavation. This study aims to provide information on the estimation of ground settlement caused by circular shaft excavation through the case analysis of circular shafts and comparison with braced cut excavation. From this study, it was found that the use of the settlement criterion of braced cut excavation as the settlement management criterion for circular shaft excavation is a conservative approach in terms of safety. But when considering the economic aspect, it may result in overdesign of the wall and therefore, a more reasonable settlement criterion can be needed for circular shaft excavation.

• Earthquakes and Structures
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• v.22 no.3
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• pp.245-261
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• 2022

Key questions to researchers interested in nonlinear analysis of skeletal structures are whether the distributed plasticity approach - albeit computationally demanding - is more reliable than the concentrated plasticity to adequately capture the extent and severity of the inelastic response, and whether force-based formulation is more efficient than displacement-based formulation without compromising accuracy. The present research focusing on performance-based seismic response of mid-span concrete bridges provides a pilot holistic investigation opting for some hands-on answers. OpenSees software is considered adopting different modeling techniques, viz. distributed plasticity (through either displacement-based or force-based elements) and concentrated plasticity via beam-with-hinges elements. The pros and cons of each are discussed based on nonlinear pushover analysis results, and fragility curves generated for various performance levels relying on incremental dynamic analyses under real earthquake records. Among prime conclusions, distributed plasticity modeling albeit inherently not relying on prior knowledge of plastic hinge length still somewhat depends on such information to ensure accurate results. For instance, displacement-based and force-based approaches secure optimal accuracy when dividing, for the former, the member into sub-elements, and satisfying, for the latter, a distance between any two consecutive integration points, close to the expected plastic hinge length. On the other hand, using beam-with-hinges elements is computationally more efficient relative to the distributed plasticity, yet with acceptable accuracy provided the user has prior reasonable estimate of the anticipated plastic hinge length. Furthermore, when intrusive performance levels (viz. life safety or collapse) are of concern, concentrated plasticity via beam-with-hinges ensures conservative predicted capacity of investigated bridge systems.

• Korea Journal of Hospital Management
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• v.28 no.2
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• pp.44-65
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• 2023

Purposes: As super-aging population and low fertility rates are threatening the sustainability of the National Health Insurance funds, enhancing the efficiency of hospital management is paramount. In the past, studies analyzing the efficiencies of hospitals primarily made inter-hospital comparisons, but it is important to assess hospitals' internal efficiency and develop improvement measures in order to attain practical improvements in hospital efficiencies. The purpose of this study is to analyze the efficiencies of specialists by medical specialty in a hospital in order to provide foundational data for efficient hospital management. Methodology/Approach: We used the activity-based costing (ABC) data and hospital statistical data from one tertiary hospital in Seoul to analyze the efficiency of specialists by medical specialty. Efficiency was analyzed and compared among specialists using the data envelopment analysis developed by Charnes, Cooper, and Rhodes (DEA-CCR) model and the slacks-based measure (SBM) models. The input variables were labor cost, material cost, and operational expenses, and the output variables were the number of outpatients, number of inpatients, outpatient revenue, and inpatient revenue. Findings: First, there was a marked deviation in efficiency across specialists. Second, there was a marked deviation in efficiency across medical specialties. Third, there was little difference in efficiency according to the specialist's sex, age, and job position. Fourth, the SBM model produced more conservative results and better explained efficiency parameters than the CCR model. Practical Implications: The efficiency of a specialist was more influenced by their medical specialty than their personal characteristics, namely sex, age, and job position. Therefore, Further research is needed to analyze the efficiencies of each subspecialty and identify factors that contribute to the variations in efficiencies across medical specialties, such as clinical practices and fee structures.