• Korean Circulation Journal
• /
• v.48 no.11
• /
• pp.989-999
• /
• 2018

Background and Objectives: We aimed to compare outcomes of complete revascularization (CR) versus culprit-only revascularization for ST-segment elevation myocardial infarction (STEMI) and multivessel disease (MVD) in the $2^{nd}$ generation drug-eluting stent (DES) era. Methods: From 2009 to 2014, patients with STEMI and MVD, who underwent primary percutaneous coronary intervention (PCI) using a $2^{nd}$ generation DES for culprit lesions were enrolled. CR was defined as PCI for a non-infarct-related artery during the index admission. Major adverse cardiovascular event (MACE) was defined as cardiovascular (CV) death, non-fatal myocardial infarction, target lesion revascularization, or heart failure during the follow-up year. Results: In total, 705 MVD patients were suitable for the analysis, of whom 286 (41%) underwent culprit-only PCI and 419 (59%) underwent CR during the index admission. The incidence of MACE was 11.5% in the CR group versus 18.5% in the culprit-only group (hazard ratio [HR], 0.56; 95% confidence interval [CI], 0.37-0.86; p<0.01; adjusted HR, 0.64; 95% CI, 0.40-0.99; p=0.04). The CR group revealed a significantly lower incidence of CV death (7.2% vs. 12.9%; HR, 0.51; 95% CI, 0.31-0.86; p=0.01 and adjusted HR, 0.57; 95% CI; 0.32-0.97; p=0.03, respectively). Conclusions: CR was associated with better outcomes including reductions in MACE and CV death at 1 year of follow-up compared with culprit-only PCI in the $2^{nd}$ generation DES era.

• Journal of Environmental Health Sciences
• /
• v.45 no.4
• /
• pp.326-339
• /
• 2019

Objectives: Minamata disease was an environmental health disaster of worldwide notoriety that occurred in Japan. The acknowledged patients total roughly 3,000, and the relieved victims currently include 77,099 cases. Still, many cases await acknowledgment or relief. The humidifier disinfectant issue is an environmental health catastrophe that took place in Korea. Over 9.98 million products spanning 43 brands of humidifier disinfectant have been sold and 835, cases have been recognized to date as relevant victims by the government. So far, 2,144 cases have been relieved by the fund of the producing companies. Four million consumers and 560,000 victims are estimated. Finding hints as to how to develop solutions in terms of fact-finding and prevention are the objectives of this study. Methods: Fields visits, interviews, and workshops as well as reference reviews have been conducted. A comparison was attempted to show the similarities and differences between the two disasters on 38 items. Results: Apparent similarities in the two disasters are the failure of industrial safety measures and governmental safety systems as well as relief systems for the victims. No comprehensive investigation was performed for all of the affected areas in Japan and all of the consumers in Korea. Both governments have tried to hide the faults and responsibilities of the companies and minimize the scale of the victims. Only after the government was changed through a general election did the new governments apologize and attempt to find political and social solutions through special relief laws. Conclusions: Over the process of each event, in the beginning, debates took place regarding the cause and the heath damages involved. For both, medical and toxicological relations are the keys while afterward finding a social solution became the subsequent issue.

• Journal of Chest Surgery
• /
• v.52 no.5
• /
• pp.335-341
• /
• 2019

Background: The endovascular approach to aortic disease treatment has been increasingly utilized in the past 2 decades. This study aimed to determine the long-term results of using the Seal thoracic stent graft. Methods: We retrospectively reviewed the outcomes of patients who underwent thoracic endovascular aortic repair or a hybrid procedure using the Seal thoracic stent graft (S&G Biotech, Seongnam, Korea) from January 2008 to July 2018 at a single institution. We investigated in-hospital mortality and the incidence of postoperative complications. We also investigated the mid-term survival rate and incidence of aorta-related complications. Results: Among 72 patients with stent grafts, 15 patients underwent the hybrid procedure and 21 underwent emergency surgery. The mean follow-up period was $37.86{\pm}30.73$ months (range, 0-124 months). Five patients (6.9%) died within 30 days. Two patients developed cerebrovascular accidents. Spinal cord injury occurred in 2 patients. Postoperative renal failure, postoperative extracorporeal membrane oxygenation support, and pneumonia were reported in 3, 1, and 6 patients, respectively. Stent-related aortic complications were observed in 5 patients (6.8%). The 1- and 5-year survival and freedom from stent-induced aortic event rates were 81.5% and 58.7%, and 97.0% and 89.1%, respectively. Conclusion: The use of the Seal thoracic stent graft yielded good mid-term results. Further studies are needed to examine the long-term outcomes of this device.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.11 no.1
• /
• pp.22-32
• /
• 2019

On offshore platforms, oil and gas leaks are apt to be the initial events of major accidents that may result in significant loss of life and property damage. To prevent accidents induced by leakage, it is vital to perform a case-specific and accurate risk assessment. This paper presents an integrated method of Ddynamic Qquantitative Rrisk Aassessment (DQRA)-using the Decision Making Trial and Evaluation Laboratory (DEMATEL)-Bayesian Network (BN)-for evaluation of the system vulnerabilities and prediction of the occurrence probabilities of accidents induced by leakage. In the method, three-level indicators are established to identify factors, events, and subsystems that may lead to leakage, fire, and explosion. The critical indicators that directly influence the evolution of risk are identified using DEMATEL. Then, a sequential model is developed to describe the escalation of initial events using an Event Tree (ET), which is converted into a BN to calculate the posterior probabilities of indicators. Using the newly introduced accident precursor data, the failure probabilities of safety barriers and basic factors, and the occurrence probabilities of different consequences can be updated using the BN. The proposed method overcomes the limitations of traditional methods that cannot effectively utilize the operational data of platforms. This work shows trends of accident risks over time and provides useful information for risk control of floating marine platforms.

• Journal of Industrial Convergence
• /
• v.18 no.6
• /
• pp.27-32
• /
• 2020

Recently, as the business using IT has increased rapidly, a lot of budget is required to operate and manage the complex IT infrastructure. There is a need for a new IT infrastructure technology that can effectively and reduce costs. In this paper, we introduce CI(Converge Infrastructure) and HCI(Hyper Converge Infrastructure) methods, which are IT infrastructure methods for simplifying information systems and reducing operational management efficiency and cost. In addition, it proposes an information system using the HCI method, a new IT infrastructure technology, and a plan to establish a disaster recovery system to provide continuity of service in the event of a disaster or failure. In addition to the introduction of major technologies for using the HCI method, the area, power consumption, and operational efficiency of the information system before and after the introduction of HCI are compared and analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.10
• /
• pp.1545-1550
• /
• 2022

In this research, a method for minimizing the replacement time of AMR (Autonomous Mobile Robot), which is used in various industrial groups such as logistics and manufacturing, was studied in the event of a LiDAR failure. In this regard, a general LiDAR exchange process was defined and a new exchange process based on the newly designed jig, which is mounted on the AMR, for the quick change of LiDAR was proposed. The experiment is conducted using commercialized AMR which was developed for application in the factory of an automobile manufacturing company. It was confirmed that LiDAR can be replaced and aligned within 24 minutes when the new exchange process is employed, which is about 76% or more shorter than the general LiDAR exchange process. As a result, we can minimize AMR downtime and overall process delays by applying the proposed process.

• Structural Monitoring and Maintenance
• /
• v.8 no.4
• /
• pp.329-344
• /
• 2021

The use of structural control devices to minimize structural response to seismic/dynamic excitations has attracted increased attention in recent years. The use of magnetorheological (MR) dampers as a control device have captured the attention of researchers in this field due to its flexibility, adaptability, easy control, and low power requirement compared to other control devices. However, little attention has been paid to the effect of configuration and number of dampers installed in a structure on responses reduction. This study assesses the control of a five-story structure using one and two MR dampers at different stories to determine the optimal damper positions and configurations based on performance indices. This paper also addresses the fail-safe current value to be applied to the MR damper at each floor in the event of feedback or control failure. The model is mathematically simulated in SIMULINK/MATLAB environment. Linear control strategies for current at 0 A, 0.5 A, 1 A, 1.5 A, 2 A, and 2.5 A are implemented for MR dampers, and the response of the structure to these control strategies for different configurations of dampers is compared with the uncontrolled structure. Based on the performance indices, it was concluded that the dampers should be positioned starting from the ground floor, then the 2^nd floor followed by 1^st and rest of the floors sequentially. The failsafe value of current for MR dampers located in lower floors (G+1) should be kept at a higher value compared to dampers at top floors for effective passive control of multi-story structures.

• Steel and Composite Structures
• /
• v.43 no.1
• /
• pp.19-30
• /
• 2022

The static strength and fatigue crack resistance of the aircraft skin structures depend on the materials used and joint type. Most of the commercial aircraft's skin panel structures are made from aluminium alloy and carbon fibre reinforced epoxy. In this study, the fatigue resistance of four joint configurations (metal/metal, metal/composite, composite/composite and composite/metal) with riveted, adhesive bonded, and hybrid joining techniques are investigated with experiments and finite element analysis. The fatigue tests were tension-tension because of the typical nature of the loads on aircraft skin panels susceptible of experimenting fatigue. Experiment results suggest that the fatigue life of hybrid joints is superior to adhesive bonded joints, and these in turn much better than conventional riveted joints. Thanks to the fact that, for hybrid joints, the adhesive bond provides better load distribution and ensures load-carrying capacity in the event of premature adhesive failure while rivets induce compressive residual stresses in the joint. Results from FE tool ABAQUS analysis for adhesive bonded and hybrid joints agrees with the experiments. From the analysis, the energy release rate for adhesive bonded joints is higher than that of hybrid joints in both opening (mode I) and shear direction (mode II). Most joints show higher energy release rate in mode II. This indicates that the joints experience fatigue crack in the shear direction, which is responsible for crack opening.

• Composites Research
• /
• v.22 no.6
• /
• pp.23-31
• /
• 2009

This paper investigated acoustic emission (AE) characteristics in association with various fracture processes of glass fiber reinforced plastic skin/ aluminum honeycomb core (GF-AH) hybrid composites under compressive and bending loads. Various failure modes such as skin layer fracture, skin/core interfacial fracture, and local plastic yield buckling and cell wall adhesive fracture occurring in the honeycomb cell wall were classified through the fracture identification in association with the AE frequency and amplitude analysis. The distribution of the event-rate in which it has a high amplitude showed a procedure of cell wall adhesive fracture, skin/core interfacial debonding and fiber breakage, whereas distribution of different peak frequencies indicated the plastic deformation of aluminum cell wall and the friction between honeycomb walls. Consequently, the fracture behaviors of GF-AH hybrid composites could be characterized through a nondestructive evaluation employing the AE technique.

• Journal of the Korean Orthopaedic Association
• /
• v.54 no.2
• /
• pp.177-181
• /
• 2019

Acute compartment syndrome, which is an orthopedic emergency, induces irreversible tissue necrosis by increasing the compartment pressure. In serious cases, this event may result in functional impairment, loss of the lower limb, and death by renal failure. When the patient initially presents with pain and swelling that are similar to deep vein thrombosis, a differential diagnosis between the two diseases is very critical. The authors encountered a case of acute compartment syndrome after anticoagulant therapy in a patient presenting with painful swelling of the left leg following a massage that was initially misdiagnosed as deep vein thrombosis. A fasciotomy was performed on this case with satisfactory results. This paper reports this case with a review of the relevant literature.