• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.1-10
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• 2023

Recently, as the demand for high-performance computers and mobile products increases, semiconductor packages are becoming high-integration and high-density. Therefore, in order to transmit a large amount of data at once, micro bumps such as flip-chip and Cu pillar that can reduce bump size and pitch and increase I/O density are used. However, when the size of the bumps is smaller than 70 ㎛, the brittleness increases and electrical properties decrease due to the rapid increase of the IMC volume fraction in the solder joint, which deteriorates the reliability of the solder joint. Therefore, in order to improve these issues, a layer that serves to prevent diffusion is inserted between the UBM (Under Bump Metallization) or pillar and the solder cap. In this review paper, various studies to improve bonding properties by suppressing excessive IMC growth of micro-bumps through additional layer insertion were compared and analyzed.

• Journal of Korean Neurosurgical Society
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• v.61 no.2
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• pp.277-281
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• 2018

Objective : Craniovertebral junctional anomalies constitute a technical challenge. Surgical opening of atlantoaxial joint region is a complex procedure especially in patients with nuchal deformity like basilar invagination. This region has actually very complicated anatomical and functional characteristics, including multiple joints providing extension, flexion, and wide rotation. In fact, it is also a bottleneck region where bones, neural structures, and blood vessels are located. Stabilization surgery regarding this region should consider the fact that the area exposes excessive and life-long stress due to complex movements and human posture. Therefore, all options should be considered for surgical stabilization, and they could be interchanged during the surgery, if required. Methods : A 53-year-old male patient applied to outpatients' clinic with complaints of head and neck pain persisting for a long time. Physical examination was normal except increased deep tendon reflexes. The patient was on long-term corticosteroid due to an allergic disease. Magnetic resonance imaging and computed tomography findings indicated basilar invagination and atlantoaxial dislocation.The patient underwent C0-C3-C4 (lateral mass) and additional C0-C2 (translaminar) stabilization surgery. Results : In routine practice, the sites where rods are bound to occipital plates were placed as paramedian. Instead, we inserted lateral mass screw to the sites where occipital screws were inserted on the occipital plate, thereby creating a site where extra rod could be bound.When C2 translaminar screw is inserted, screw caps remain on the median plane, which makes them difficult to bind to contralateral system. These bind directly to occipital plate without any connection from this region to the contralateral system.Advantages of this technique include easy insertion of C2 translaminar screws, presence of increased screw sizes, and exclusion of pullout forces onto the screw from neck movements. Another advantage of the technique is the median placement of the rod; i.e., thick part of the occipital bone is in alignment with axial loading. Conclusion : We believe that this technique, which could be easily performed as adjuvant to classical stabilization surgery with no need for special screw and rod, may improve distraction force in patients with low bone density.

• Journal of Korean Foot and Ankle Society
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• v.18 no.2
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• pp.56-61
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• 2014

Purpose: This study was conducted among patients with moderate to severe hallux valgus who underwent distal chevron osteotomy and groups of patients with or without Akin osteotomy were compared for evaluation of the relationship between their radiological and clinical outcomes. Materials and Methods: From January 2009 to January 2012, among patients with moderate to severe hallux valgus who underwent distal chevron osteotomy at our institution, 28 cases with additional Akin osteotomy and 35 cases without Akin osteotomy available to follow up of more than one year were included in this study. For radiologic evaluation, hallux valgus angle, 1, 2 intermetatarsal angle, and hallux interphalangeal angle were measured before and after surgery. For clinical assessment, visual analogue scale score, American Orthopaedic Foot and Ankle Society score, subjective satisfaction of the patients, and passive range of motion of the first metatarsophalangeal joints were evaluated. Results: At the final follow up, correction of valgus hallux angle and 1, 2 intermetatarsal angle was obtained from radiation results of both groups and it was found that patients who underwent Akin osteotomy showed radiographically larger angle correction but less subjective satisfaction. Conclusion: Patients with moderate to severe hallux valgus who underwent distal chevron osteotomy showed not only functional but also radiographically satisfactory results, and patients who underwent additional Akin osteotomy showed decreased subjective satisfaction. Therefore, if an incongruent first metatarsophalangeal joint is not observed, distal chevron osteotomy without Akin osteotomy seems preferable.

• Journal of Broadcast Engineering
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• v.12 no.5
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• pp.445-451
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• 2007

This study was started to not only resolve structural problems such as lack of contents, an unstable structure of earnings, and reduction of an additional market in Korean film industry through revitalizing digital cinema, but also make digital cinema become a power for growing Korean film industry furthermore. In the section of revitalizing digital cinema production, I suggest that expanding an audience base of low budget art cinema using digital technology will contribute to diversity film contents, and joint production with broadcasters by digital technology will expedite growing film industry as well as revitalizing digital cinema production. In the section of revitalizing digital cinema distribution, I insist, we should make effort positively to build reasonable hold-back and so on in order that film industry's positive participation in the market of digital film distribution and new media such as DMB or IP-TV may become an additional market to film industry. In conclusion, we can gain a foothold to leap toward a Position of cultural technology Power through efforts to resolve problems inherent in digital cinema.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.40-46
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• 2020

Safe security technology is required for the startup ecosystem according to the construction and service of a joint open platform in the financial sector. Financial industry standard open API recommends that payment-related fintech companies develop/apply additional security technologies to protect core API authentication keys in the mutual authentication process. This study proposes an enhanced API security protocol using multiple channels. It was designed in consideration of the compatibility of heterogeneous platforms by further analyzing the problems and weaknesses of existing open API related research. I applied the method of concealment to remove the additional security channels into a single channel of the existing security protocols. As a result of the performance analysis, the two-way safety of the communication session of the multi-channel and the security of the man-in-the-middle attack of the enhanced authentication key were confirmed, and the computational performance of the delay time (less than 1 second) in the multi-session was confirmed.

• The Journal of the Korean bone and joint tumor society
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• v.3 no.2
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• pp.98-104
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• 1997

We carried out a prospective study of the effectiveness of a diagnostic strategy in thirty consecutively seen patients who had skeletal metastasis. The diagnostic strategy consisted of the recording of a medical history, physical examination, routine laboratory analysis, plain radiography of the involved bone and chest, whole-body technetium-99m-phosphonate bone scintigraphy, abdominal ultrasound, computed tomography of the chest, abdomen and pelvis, fiberbronchoscopy and fibergastroscopy. After this evaluation, a biopsy of the most accessible osseous lesion was done in twenty four patients. On the basis of the our diagnostic strategy, we were able to identify the primary site of the malignant tumor in nineteen patients(63%). The laboratory values were non-specific in all patients. The history and physical examination revealed the occult primary site of the malignant tumor in one patient(3.3%) who had carcinoma of the breast. Plain radiographs of the chest established the diagnosis of carcinoma of the lung in three patients(9.9%). Computed tomography of the chest identified an additional three primary carcinoma of the lung(9.9%). Fiberbronchoscopy identified an additional one primary carcinoma of the lung(3.3%). Abdominal ultrasound established the diagnosis in three patients(9.9%). Computed tomography of the abdomen and pelvis established the diagnosis in four patients(13.2%). Fibergastroscopy established the diagnosis in two patients(6.6%). Examination of the biopsy tissue established the diagnosis in one patient(3.3%). So we recommend to perform plain radiographs of chest, abdominal ultrasound, chest C-T, abdomino-pelvic C-T, fiber-bronchoscopy, fibergastroscopy sequentially.

• Earthquakes and Structures
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• v.20 no.2
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• pp.133-148
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• 2021

The paper presents a simplified force-based seismic design procedure for the preliminary design of steel haunch retrofitting for the seismic upgrade of deficient RC frames. The procedure involved constructing a site-specific seismic design spectrum for the site, which is transformed into seismic base shear coefficient demand, using an applicable response modification factor, that defines base shear force for seismic analysis of the structure. Recent experimental campaign; involving shake table testing of ten (10), and quasi-static cyclic testing of two (02), 1:3 reduced scale RC frame models, carried out for the seismic performance assessment of both deficient and retrofitted structures has provided the basis to calculate retrofit-specific response modification factor Rretrofitted. The haunch retrofitting technique enhanced the structural stiffness, strength, and ductility, hence, increased the structural response modification factor, which is mainly dependent on the applied retrofit scheme. An additional retrofit effectiveness factor (ΩR) is proposed for the deficient structure's response modification factor Rdeficient, representing the retrofit effectiveness (ΩR=Rretrofitted /Rdeficient), to calculate components' moment and shear demands for the retrofitted structure. The experimental campaign revealed that regardless of the deficient structures' characteristics, the ΩR factor remains fairly the unchanged, which is encouraging to generalize the design procedure. Haunch configuration is finalized that avoid brittle hinging of beam-column joints and ensure ductile beam yielding. Example case study for the seismic retrofit designs of RC frames are presented, which were validated through equivalent lateral load analysis using elastic model and response history analysis of finite-element based inelastic model, showing reasonable performance of the proposed design procedure. The proposed design has the advantage to provide a seismic zone-specific design solution, and also, to suggest if any additional measure is required to enhance the strength/deformability of beams and columns.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.887-908
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• 2022

In order to confirm the effects of economic growth and environmental improvement, this study analyzed the existence of environmental Kuznets curve (EKC) for SO₂ emission, greenhouse gas emission, and waste generation in OECD countries. As a result of panel analysis, the shape of the EKC were different depending on environmental pollutants. SO₂ generated peaks relatively early in economic growth, and the peak of greenhouse gas emissions was showed in higher income level. But both emissions showed the a complete inverted U-shaped curve decreasing after the peak. On the other hand, for waste, there was no environmental Kuznets curve that could confirm the peak. Therefore, this study confirmed that it is difficult to expect a voluntary reduction in all environmental pollutants, and additional global joint efforts are needed to pass the peak. In particular, since waste has a greater impact on population density and industrial structure than income level, additional policy efforts are needed to reduce generation and create a resource circulation system.

• Steel and Composite Structures
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• v.52 no.2
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• pp.135-143
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• 2024

Once the foundation displacement of the transmission tower occurs, additional stress will be generated on the tower members, which will affect the seismic response of transmission tower-line systems (TTLSs). Furthermore, existing research has shown that the reciprocating slippage of joints needs to be considered in the seismic analysis. The hysteretic behavior of joints is obtained by model tests or numerical simulations, which leads to the low modeling efficiency of TTLSs. Therefore, this paper first utilized numerical simulation and model tests to construct a BP neural network for predicting the skeleton curve of joints, and then a numerical model for a TTLS considering the bolt slippage was established. Then, the seismic response of the TTLS under foundation displacement was studied, and the member stress changes and the failed member distribution of the tower were analyzed. The influence of foundation displacement on the seismic performance were discussed. The results showed that the trained BP neural network could accurately predict the hysteresis performance of joints. The slippage could offset part of the additional stress caused by foundation settlement and reduce the stress of some members when the TTLS with foundation settlement was under earthquakes. The failure members were mainly distributed at the diagonal members of the tower leg adjacent to the foundation settlement and that of the tower body. To accurately analyze the seismic performance of TTLSs, the influence of foundation displacement and the joint effect should be considered, and the BP neural network can be used to improve modeling efficiency.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.365-372
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• 2004

The purpose of this study was to implement HACCP system to foodservice of W and D elementary schools with joint-lunch management system in Kyungsan area. Steamed rice with squid was selected and Control Action, Monitoring Procedure and Control measure were identified based on HACCP flowchart to produce safe and healthy food. It was suggested that frozen squid must be thawed under the cold running city water and kept temperature below 1$0^{\circ}C$ and receiving/thawing procedure has to be done within 30 min. Raw vegetables must be washed under three-tube wash stand and whole prepreparation procedures should be done in 20 minutes. Clean and sanitize all the equipment and utensils before and after handling squid. Knives and cutting boards for vegetable and squid should be classified. Sauce for steamed rice with squid should be heated about 21 minutes to reach the temperature of 94$^{\circ}C$ before serving and internal temperature of food must be kept above 84.4$^{\circ}C$ during serving. The ideal temperature of kitchen should be remained 15∼18$^{\circ}C$. The underground water has to be excluded to minimize the risk of contamination in the foodservice facility and the prepreparation place must be separated with cooking place. Also, Personal hygiene Practice should be check in each stage. Further, additional research needs to be conducted to determine models for HACCP implementation for different menu.