• Journal of Advanced Navigation Technology
• /
• v.25 no.3
• /
• pp.242-247
• /
• 2021

Major countries in space field such as the United States, China and Russia have not only general ground-based space capabilities, but also maritime-based space capabilities. Maritime-based space systems include a maritime-based space surveillance system, a maritime-based space launch vehicle, and a maritime-based space information transmission system, and these maritime-based systems complement the ground-based space systems. Therefore, in this paper, we analyze the maritime-based space capabilities of major countries, and propose the future direction for south Korea's maritime-based space capabilities. The maritime-based space system is essential due to the geographical characteristics of south Korea, which has three sides of the ocean, and it is considered an one of important strategic element to become the seven major country in the space field.

• Design Convergence Study
• /
• v.18 no.3
• /
• pp.1-14
• /
• 2019

General finger splint manufactured and sold domestically could have been of great help to patients with disabilities due to damage to the body's. However, it reminded the wearer of his disability that he wanted to hide. This has had a negative effect on the psychological side of self-absorption and depression. If this avoids or rejects wearing, the role of ancillary rehabilitation is lost. This does not meet the user's requirements. Thus, in this study, 3D printing was used to better reflect user requirements. Next, the study examined existing prior studies to identify the characteristics and criteria of each study. It also examined medical finger aids that were being sold in the auxiliary device market. The assessment criteria were derived by compiling and interpreting user surveys of each finger splint device. Based on the evaluation criteria derived, the design guidelines for finger splint were presented using FDM-style 3D printers. Finally, we proposed a finger splint design according to the proposed design guideline.

• Current Photovoltaic Research
• /
• v.8 no.4
• /
• pp.124-128
• /
• 2020

Output power of photovoltaic (PV) modules installed outdoors decreases every year due to environmental conditions such as temperature, humidity, and ultraviolet irradiations. In order to promote the installation of PV modules, the reliability must be guaranteed. One of the important factors affecting reliability is intermetallic compounds (IMC) layer formed in ribbon solder joint. For this reason, various studies on soldering properties between the ribbon and cell have been performed to solve the reliability deterioration caused by excessive growth of the IMC layer. However, the IMC layer of the PV module interconnected by multi-wires has been studied less than using the ribbon. It is necessary to study soldering characteristics of the multi-wire module for improvement of its reliability. In this study, we analyzed the growth of IMC layer of the PV module with multi-wire and the degradation of output power through damp-heat test. The fabricated modules were exposed to damp-heat conditions (85 ºC and 85 % relative humidity) for 1000 hours and the output powers of the modules before and after the damp-heat test were measured. Then, the process of dissolving ethylene vinyl acetate (EVA) as an encapsulant of the modules was performed to observe the IMC layer. The growth of IMC layer was evaluated using OM and FE-SEM for cross-sectional analysis and EDS for elemental mapping. Based on these results, we investigated the correlation between the IMC layer and output power of modules.

• Tunnel and Underground Space
• /
• v.31 no.4
• /
• pp.211-220
• /
• 2021

Tunnel collapse often occurs during deep underground tunneling (> 40 m depth) in South Korea. Natural cavities as well as water supply pipes, sewer pipes, electric power cables, artificial cavities created by subway construction are complexly distributed in the artificial ground in the shallow depths of the urban area. For deep tunnel excavation, it is necessary to understand the properties of the ground which is characterized by porous elements and various geological structures, and their influence on the stability of the ground. This study analyzed geological factors for risk assessment in deep excavation in South Korea based on domestic and overseas case study. As a result, a total of 7 categories and 38 factors were derived. Factors with high weights were fault and fault clay, differential stress, rock type, groundwater and mud inrush, uniaxial compressive strength, cross-sectional area of tunnel, overburden thickness, karst and valley terrain, fold, limestone alternation, fluctuation of groundwater table, tunnel depth, dyke, RQD, joint characteristics, anisotropy, rockburst and so forth.

• Journal of Arbitration Studies
• /
• v.32 no.1
• /
• pp.25-42
• /
• 2022

The modern arbitration practice recognises the need for a faster and simplified procedural framework for international disputes with fairly low amounts at stake. This has driven several institutions to expand their offer of procedural guidelines with a simplified set of rules that would fit this purpose. Expedited arbitration is increasingly used by parties and is growing in popularity. The basic idea behind establishing expedited arbitration rules is to create the possibility for the parties to a dispute to agree on a simplified and streamlined procedure and to have an arbitration award issued within a short period. The associated cost savings for the parties is another benefit. The importance of developing rules for expedited dispute resolution has recently also been considered by the UNCITRAL Working Group II, in light of the "increasing demand to resolve simple, low-value cases by arbitration" and "the lack of international mechanisms cope with such disputes." As a result, the UNCITRAL 2021 Expedited Arbitration Rules (UNCITRAL EAR) took effect on September 19, 2021. The EAR was adopted by the Commission on 21 July 2021 and, next to UNCITRAL's well-known instruments like the Arbitration Rules (UAR) and the Model Law, represent another chapter in the Commission's impactful work in the field of international arbitration. Overall, the UNCITRAL EAR has great potential to meet the need for more flexible and efficient arbitration proceedings, primarily because they provide the tribunal with strong managerial powers while still leaving room for consultation with the parties. However, parties must remember that not all disputes may be suitable for expedited arbitration, and disputes that are complex or have the possibility of being joint or consolidated may not benefit from simplified procedures and tight deadlines. This article will outline the core features and characteristics of the UNCITRAL EAR.

• Journal of Dental Anesthesia and Pain Medicine
• /
• v.22 no.4
• /
• pp.289-294
• /
• 2022

Background: Orofacial pain is defined as pain felt in the soft or hard tissues of the head, face, mouth, and neck. Chronic orofacial pain is often challenging to diagnose and difficult to treat. Due to the lack of available information about the prevalence and clinical form of orofacial pain, this study aimed to evaluate the characteristics of chronic orofacial pain in patients presenting at the Department of Oral Medicine of Shahid Beheshti Dental School between 2012 and 2022. Methods: In this retrospective study, we evaluated the files of 121 patients at the Department of Oral and Maxillofacial Diseases of Shahid Beheshti Dental School, which were completed during 2012-2022. We extracted the required information from these files. Results: In total, 121 files were included in the study (30 male, 91 female). The mean age of the patients was 43.68 ± 16.79 years. The most common diagnosis in patients with chronic orofacial pain was temporomandibular disorders (TMD) (55.3%). Among pain-related factors, psychological factors showed the highest frequency (30.5%). Opening and closing (43.8%) had the highest frequency among factors that increased pain, and the rest (6.6%) had the highest frequency among the factors that reduced pain. Most patients experienced unilateral pain over the masseter area. Most patients reported their pain intensity to be greater than 7 in the verbal analog scale (VAS). The most common symptom associated with pain was joint noise (37.1%). Conclusion: A ten-year retrospective evaluation of patient files showed that more than half of the patients with chronic orofacial pain had TMD.

• The Research Journal of the Costume Culture
• /
• v.30 no.3
• /
• pp.403-413
• /
• 2022

The purpose of this study was to develop a 3D mesh-type impact protection pad with excellent motion adaptability and functionality by applying 3D printing technology. The hexagonal 3D mesh, which constitutes the basic structure of the pad, comprises two types: small and large. The bridge connecting the basic units was designed as the I-type, V-type, IV-type, and VV-type. After evaluating the characteristics of the bridge, it was found that the V-type bridge had the highest flexibility and tensile elongation. The hip joint pad and knee pad were completed by combining the hexagonal 3D mesh structure with the optimal bridge design. The impact protection pad was printed using a fused deposition modeling-type 3D printer with a filament made of thermoplastic polyurethane material, and the protection pad's performance was evaluated. When an impact force of approximately 6,500N was applied to the pad, the force attenuation percentage was 78%, and when an impact force of approximately 8,000N was applied, the force attenuation percentage was 75%. Through these results, it was confirmed that the 3D-printed impact protection pad with a hexagonal 3D mesh structure connected by a V-shaped bridge developed in this study can adapt to changes in the body surface according to movement and provides excellent impact protection performance.

• Clinics in Shoulder and Elbow
• /
• v.25 no.2
• /
• pp.101-105
• /
• 2022

Background: Rotator cuff tears cause pathologies of the long head of the biceps tendon (LHBT). One of the surgical treatments for such a tear is LHBT tenodesis to the humerus. This study aims to compare simultaneous rotator cuff repair and LHBT tenodesis with or without detachment of the proximal end of the LHBT (PELHBT) from its site of adhesion to the glenoid. Methods: This retrospective study involved patients affected by LHBT pathology with rotator cuff tear. The patients were divided into two groups, with or without PELHBT detachment from the glenoid. Therapeutic outcomes were investigated by evaluation of patient satisfaction, pain based on visual analog scale, shoulder function based on Constant score and simple shoulder test, and biceps muscle strength based on the manual muscle testing grading system before surgery, at 6 months, and at the final visit after surgery. Results: Groups 1 and 2 comprised 23 and 26 patients, respectively, who showed no significant differences in demographic characteristics (p>0.05). Shoulder function, biceps muscle strength, pain, and satisfaction rate improved over time (p<0.05) but were not significantly different between the two groups (p>0.05). No post-surgical complication was found in either group. Conclusions: There was no difference in final outcomes of tenodesis with or without detachment of the PELHBT from the supraglenoid tubercle. Such tendon detachment is not necessary.

• Journal of Korea Trade
• /
• v.24 no.6
• /
• pp.1-18
• /
• 2020

Purpose - This study investigates whether a listing effect exists in cross-border M&As and whether the effect can be attributed to the uncertainty of the GDP growth rate in the target firm's home country. We apply a joint variable analysis using M&A announcement data from the Korea Exchange (KRX), Shanghai Stock Exchange (SSE), and the Taiwan Stock Exchange (TWSE) from 2004 to 2013. We also conduct an event study using the measure of the uncertainty of the GDP growth rate (based on IMF statistics) in 55 target countries. Design/methodology - We measure the abnormal return (AR) using the market-adjusted model. We test the significance of the AR and the cumulative abnormal return (CAR) using a one-sample t-test. We examine the characteristics of the CARs depending on whether the target company is listed by applying a difference analysis using CAR as a test variable. In addition, we set CAR (-5, +5) as a dependent variable to identify the cause of the listing effect, and test both the financial characteristic variables of the acquirer and the collective characteristic variables of the merger as independent variables in the multiple regression analysis. Findings - First, we find the listing effect of cross-border M&As in the KRX, SSE, and TWSE, which represent the capital markets in Korea, China, and Taiwan, respectively. This listing effect persists during the global financial crisis and has a negative effect on the wealth of acquiring shareholders, especially when the target countries are emerging markets. Second, greater uncertainty regarding the target countries' economic growth in cross-border M&As has a negative effect on the wealth of acquiring firms' shareholders. Third, our empirical analysis demonstrates that the listing effect is attributable to the fact that firms listed in a target country with greater uncertainty of economic growth are more directly and greatly exposed to uncertain capital markets through stock markets, than are unlisted firms. Originality/value - This study is significant in that it presents a new strategic perspective in the study of cross-border M&As by demonstrating empirically that the listing effect is attributable to the uncertainty regarding the economic development of the target firms' home countries.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.7
• /
• pp.105-112
• /
• 2021

Reduction of weld distortions and increase in productivity are some of the major goals of the shipbuilding industry. To address these issues, many researchers have attempted to apply new welding processes. In the shipbuilding industry, steel is the candidate material of choice owing to its good weldability. However, conventional welding techniques are not feasible for avoiding welding problems. Tip-rotating arc welding is one of the high-efficiency welding process that has several advantages, such as high welding speed, high melting rate, low heat input, and less distortion. The present study investigates the influence of the welding variables on the weld characteristics of tip-rotating arc welding. Welding was performed using EH36 as the base metal and SM-70s as the filler metal, which are widely used in shipbuilding. Basic experiments were conducted to understand the effects of the major welding variables, such as welding and tip-rotating speeds. The distortion and mechanical properties of the optimal welding conditions were used to evaluate the tip-rotating arc welding performance. Consequently, the feasibility of the tip-rotating arc welding process for joining steel components was investigated, so that the optimized welding conditions could be applied directly to ship body welding to enhance the quality of the welded joints.