• Journal of the Korea Society of Computer and Information
• /
• v.27 no.2
• /
• pp.125-134
• /
• 2022

In this paper, we propose an extension method of the BR2K technique for enhancing the robustness of blockchain application services. The BR2K (Blockchain application, Replication & Recovery technique using Kubernetes) technique was recently developed to support the robustness of blockchain services through service replication and rapid restart. The proposed technique extends the existing BR2K technique to provide a state version, which is meta-information about the service state, and a method for safely managing it, and use the state version to determine the timing for service state recovery. Also, the technique provides systematic service state backup for service recovery and joining of new service nodes by utilizing the version information and the service registry which acts as a service recovery center in the BR2K technique. Based on this, it is possible to support new service nodes to join the replication service with consistency. As a result, new service nodes can be quickly added to the BR2K service in operation, enhancing the robustness of the BR2K service. In addition, the extended method is applied to the pilot blockchain application service and tested in a Kubernetes environment composed of virtual machines to confirm the validity of service replication consistency and rapid service recovery in the event of node failures.

• Archives of Plastic Surgery
• /
• v.49 no.3
• /
• pp.346-351
• /
• 2022

Background Postmastectomy breast reconstruction (PMR) increases patient satisfaction, quality of life, and psychosocial well-being. There is scarce data regarding the safety of PMR in chronic anticoagulated patients. Perioperative complications can reduce patient satisfaction; therefore, it is important to elucidate the safety of PMR in these patients. Methods A retrospective case-control study of patients who underwent PMR with implants and were on chronic anticoagulation was performed at our institution. Inclusion criteria were women ≥ 18 years old. Exclusion criteria included autologous reconstructions, lumpectomy, and oncoplastic procedures. Two controls for every one patient on anticoagulation were matched by age, body mass index, radiotherapy, smoking history, type of reconstruction, time of reconstruction, and laterality. Results From 2009 to 2020, 37 breasts (20 patients) underwent PMR with implant-based reconstruction and were on chronic anticoagulation. A total of 74 breasts (40 patients) who had similar demographic characteristics to the cases were defined as the control group. Mean age for the case group was 53.6 years (standard deviation [SD] = 16.1), mean body mass index was 28.6 kg/m² (SD = 5.1), and 2.7% of breasts had radiotherapy before reconstruction and 5.4% after reconstruction. Nine patients were on long-term warfarin, six on apixaban, three on rivaroxaban, one on low-molecular-weight heparin, and one on dabigatran. The indications for anticoagulation were prior thromboembolic events in 50%. Anticoagulated patients had a higher risk of capsular contracture (10.8% vs. 0%, p = 0.005). There were no differences regarding incidence of hematoma (2.7% vs. 1.4%, p = 0.63), thromboembolism (5% vs. 0%, p = 0.16), reconstructive-related complications, or length of hospitalization (1.6 days [SD = 24.2] vs. 1.4 days [SD = 24.2], p = 0.85). Conclusion Postmastectomy implant-based breast reconstruction can be safely performed in patients on chronic anticoagulation with appropriate perioperative management of anticoagulation. This information can be useful for preoperative counseling on these patients.

• Journal of Aerospace System Engineering
• /
• v.16 no.3
• /
• pp.99-104
• /
• 2022

Aircraft pylon connects the engine or external stores to the main wing, and transfers the load acting on the pylon to the main structure of the aircraft. In particular, it should perform the function of separating the external store mounted on the pylon in case of emergency or mission performance. At this time, if the separation of the external store is not performed properly due to peripheral air flow or functional problems during the separation process of the external store, it may seriously impact the survivability of the aircraft. For this reason, to apply an external attachment to an aircraft, it is necessary to prove the stability of the external attachment in the separation situation in advance. In this paper, we present the result of the ground separation test performed to confirm that the external fuel tank, which is an external attachment, can be safely separated from the pylon. As a result of the test, the separation movement of the external fuel tank was measured with a high-speed camera, and the stability of the separation of the external fuel tank from the pylon were confirmed through the ground separation test. Additionally, the test result provides basic data for the stability evaluation of the separation of external attachments in actual aircraft.

• Journal of the Korea Institute of Building Construction
• /
• v.22 no.2
• /
• pp.161-169
• /
• 2022

The government [3] specifies steel pipe scaffolding as conventional scaffolding and is promoting the installation of system scaffolding, an integrated work platform, and avoidance of the use of steel pipe scaffolding as much as possible. However, in places where equipment cannot enter, such as power plants and plant sites, places the structure is complex, and places where scaffolding cannot be stacked on the ground, there is no choice but to install steel pipe scaffolding. When installing steel pipe scaffolding on an H-beam structure at a high place, the performance of the steel frame clamp is very important in order to form a work space which workers can work safely. In this study, the displacement magnitude and tensile load of members in each installation direction of the clamp for steel frame were verified through performance tests and structural analysis modeling. As a result, it was confirmed that the performance for each installation direction satisfies the safety certification standard tensile load of 10,000N. Although the performance value is satisfactory, deformation of the attachment pressing bolt was verified and was confirmed to have minimal deformation. Thus, to ensure the load is properly to the attachment body, the clamp for a steel frame must be installed in the direction in which the load is transmitted.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.48 no.4
• /
• pp.225-231
• /
• 2022

Objectives: This study aims to evaluate the efficacy and safety of two types of sandblasted with large-grit and acid-etched (SLA) surface implants with different surface roughness. Patients and Methods: This study was conducted based on a clinical record review of 55 patients (mean age, 53.00 years). A total of 80 SLA surface implants was placed. Among the 80 implants, 38 implants placed in 29 subjects had surface roughness (Ra) of 3.09 ㎛ (test group, TG), while the other 42 implants placed in 31 subjects had a surface roughness (Ra) of 2.50 ㎛ (control group, CG). A comparison was made of implant primary/secondary stability; success and survival rates; marginal bone loss; and soft tissue assessment including probing pocket depth (PPD), plaque index (PI), gingival index (GI), and bleeding on probing (BOP) between the groups at 1 year after implant placement. Results: Among the implants that were initially registered, 1 from the TG and 4 from the CG dropped out, leaving 37 implants in the TG and 38 implants in the CG to be traced and analyzed. Although 1 TG case showed unstable primary stability, all cases showed stable secondary stability. Success and survival rates at 1 year after implant placement were 100% in both groups. Marginal bone loss was 0.07 mm and 0.00 mm for the TG and CG, respectively, but the difference was not significant. Among the several parameters for evaluation of soft tissue, the TG showed lower PI at 1 year after implant placement (TG=0.00, CG=0.29; P=0.0004), while the remaining categories showed no significant difference between the groups. Conclusion: This study shows that the two types of SLA implants with different surface roughness have no difference in efficacy or safety. Therefore, both of the implants can be used safely and with promising outcomes.

• Journal of Korea Water Resources Association
• /
• v.54 no.11
• /
• pp.933-942
• /
• 2021

The surface image velocimetry was developed to measure river flow velocity safely and effectively in flood season. There are a couple of methods in the surface image velocimetry. Among them the spatio-temporal image velocimetry is in the spotlight, since it can estimate mean velocity for a period of time. For the spatio-temporal image velocimetry analyzes a series of images all at once, it can reduce analyzing time so much. It, however, has a little drawback to find out the main flow direction. If the direction of spatio-temporal image does not coincide to the main flow direction, it may cause singnificant error in velocity. The present study aims to propose a new method to find out the main flow direction by using a fast Fourier transform(FFT) to a spatio-temporal (image) volume, which were constructed by accumulating the river surface images along the time direction. The method consists of two steps; the first step for finding main flow direction in space image and the second step for calculating the velocity magnitude in main flow direction in spatio-temporal image. In the first step a time-accumulated image was made from the spatio-temporal volume along the time direction. We analyzed this time-accumulated image by using FFT and figured out the main flow direction from the transformed image. Then a spatio-temporal image in main flow direction was extracted from the spatio-temporal volume. Once again, the spatio-temporal image was analyzed by FFT and velocity magnitudes were calculated from the transformed image. The proposed method was applied to a series of artificial images for error analysis. It was shown that the proposed method could analyze two-dimensional flow field with fairly good accuracy.

• Journal of Service Research and Studies
• /
• v.12 no.2
• /
• pp.23-37
• /
• 2022

Based on the service scenario proposed by the existing Kim Tae-wan (2018) who can safely evacuate inmates with the help of a mobile application linked to a fire detection system in the event of a fire, the final purpose of this study is to develop the scenario by incorporating more realistic scenarios with mobile stimuli that can help them escape or act through the Delph In addition, to make the scenarios produced more realistic considering the structure and copper lines of a typical building, expert scenario verification and Delphi technique were applied to exclude unnecessary or impractical aspects of the existing scenarios. The results of the second Delphi survey showed that the primary psychology that could be seen at the time of the fire alarm were doubts, safety concerns and alarm, and the results of the second Delphi survey were analyzed, and the satisfaction of the content adequacy (CVR), convergence, and consensus was derived. Finally, this was applied to create a scenario in which a mobile application was assisted to evacuate the fire response phase. This study will allow the use of methods to increase the evacuation rate of those who are in the event of a fire.

• Journal of Industrial Convergence
• /
• v.20 no.11
• /
• pp.85-93
• /
• 2022

As of the end of 2019, the total population nationwide was 51,849,861, and over the past five years, the population per household has decreased by 1.52% annually from 2.45 in 2015 to 2.31 in 2019. Looking at the current status of population distribution by age group, Busan metropolitan city had the highest proportion of senior citizens aged 65 or older at 18.2%, and Sejong Special Self-Governing city had the lowest at 9.4%. In particular, as of 2019, the population of the mobility handicapped was 15,219,000 nationwide, showing a ratio of about 29.4% of the total population. Therefore, it is important to secure the right to move according to the mobile facilities so that the mobility handicapped can move safely and conveniently. Against this background, this study places value on transportation welfare facilities centered on the mobility handicapped for safe and convenient movement, and in particular, in proposing measures to cope with the entry of an aging society and the continuous increase of the mobility handicapped, the transportation facilities, The purpose of this study is to analyze the impact of welfare facilities on the mobility handicapped and suggest implications. As a research method, the results of statistical analysis methods were presented through major preceding studies and expert surveys.

• Journal of Platform Technology
• /
• v.11 no.3
• /
• pp.24-31
• /
• 2023

Recently, interest in UAM (Urban Air Mobility, UAM), which can take off and land vertically in the operation of urban air transportation systems, has been increasing. Therefore, various start-up companies are developing related technologies as eco-friendly future transportation with advanced technology. However, studies on ways to increase safety in the operation of UAM are still insignificant. In particular, efforts are more urgent to improve the safety of risks generated in the process of attempting to land in the city center by UAM equipped with autonomous driving. Accordingly, this study proposes a plan to safely land by avoiding dangerous region that interfere when autonomous UAM attempts to land in the city center. To this end, first, the latitude and longitude coordinate values of dangerous objects observed by the sense of the UAM are calculated. Based on this, we proposed to convert the coordinates of the distorted planar image from the 3D image to latitude and longitude and then use the calculated latitude and longitude to compare the pre-learned feature descriptor with the HOG (Histogram of Oriented Gradients, HOG) feature descriptor to extract the dangerous Region. Although the dangerous region could not be completely extracted, generally satisfactory results were obtained. Accordingly, the proposed research method reduces the enormous cost of selecting a take-off and landing site for UAM equipped with autonomous driving technology and contribute to basic measures to reduce risk increase safety when attempting to land in complex environments such as urban areas.

• Journal of the Korea Society for Simulation
• /
• v.19 no.2
• /
• pp.29-41
• /
• 2010

Due to the recent technological advance, new types of AS/RS which can handle containers are being developed, and it is expected that they will be applied to related industries before long. Some companies and institutes in our country have constructed pilot systems for high-density-high-stacking systems and tested them to develop AS/RS-typed warehouses for containers. Along with this kind of construction efforts, development of rules to operate such systems efficiently and safely is also important. When outward-bound shipment is scheduled in container port, re-marshalling which rearranges containers in the yard to make shipment easy is conducted. In this paper, operating rules for the re-marshalling as well as simulation experiments to evaluate the performance of the rules are presented. We suggested two kinds of alternative sets of operating rules for re-marshalling and described the relevant logics corresponding to all possible cases for each alternative of operating rules. Through various simulation experiments, we found that each alternative has the merits and demerits at the same time and we could not say the one is always superior to the other. As a useful strategy, changing the applying operating rule is recommended from moment to moment depending on the expected number of operations at the landside input/output position.