• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.61-68
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• 2012

Recommender Systems have gained much popularity among researchers and is applied in a number of applications. The exponential growth of users and products poses some key challenges for recommender systems. Recommender Systems mostly suffer from scalability and accuracy. The accuracy of Recommender system is somehow inversely proportional to its scalability. In this paper we proposed a Context Aware Hybrid Recommender System using matrix reduction for Hybrid model and clustering technique for predication of item features. In our approach we used user item-feature rating, User Demographic information and context information i.e. specific time and day to improve scalability and accuracy. Our Algorithm produce better results because we reduce the dimension of items features matrix by using different reduction techniques and use user demographic information, construct context aware hybrid user model, cluster the similar user offline, find the nearest neighbors, predict the item features and recommend the Top N- items.

• Archives of Plastic Surgery
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• v.42 no.4
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• pp.446-452
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• 2015

Background Various techniques are used for performing breast reduction. Wise-pattern and vertical scar techniques are the most commonly employed approaches. However, a vertical scar in the mid-lower breast is prominent and aesthetically less pleasant. In contrast, a semicircular horizontal approach does not leave a vertical scar in the mid breast and transverse scars can be hidden in the inframammary fold. In this paper, we describe the experiences and results of semicircular horizontal breast reductions performed by a single surgeon. Methods Between September 1996 and October 2013, our senior author used this technique in 38 cases in the US and at our institution. We used a superiorly based semicircular incision, where the upper skin paddle was pulled down to the inframammary fold with the nipple-areola complex pulled through the keyhole. Results The average total reduction per breast was 584 g, ranging from 286 to 794 g. The inferior longitudinal pedicle was used in all the cases. The average reduction of the distance from the sternal notch to the nipple was 13 cm (range, 11-15 cm). The mean decrease in the bra cup size was 1.7 cup sizes (range, a decrease of 1 to 3). We obtained very satisfactory results with a less noticeable scar, no complication such as necrosis of the nipple or the skin flap, wound infection, aseptic necrosis of the breast tissue, or wound dehiscence. One patient had a small hematoma that resolved spontaneously. Conclusions This technique is straightforward and easy to learn, and offers a safe, effective, and predictable way for treating mammary hypertrophy.

• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.238-249
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• 2003

Eureka 147 DAB system based on the orthogonal frequency division multiplexing (OFDM) was adopted as the transmission scheme for terrestrial digital multimedia broadcasting (DMB) system in Korea. The OFDM has several advantages comparing to the single carrier modulation. However, its high Peak-to-average power ratio (PAPR) increases the complexity of the D/A and A/D converters and reduces the efficiency of the high power amplifier To reduce the high PAPR of OFDM, various techniques such as clipping, peak windowing, companding, selected mapping (SLM), Partial transmit sequences (PTS), etc. have been proposed. In this paper, we propose modified configurations of SLM and PTS for effective implementation and evaluate the performance on the PAPR reduction of DMB system. The simulation results show that the modified SLM (MSLM) has merits in reducing the amount of computation and hardware complexity due to the reduction of the number of vector $P^{(U)}$, while satisfying the same performance and maintaining the same required bits (RB) for side information. With the same amount of computation and the same RB, the modified PTS (MPTS) is also shown to be better than PTS in the performance of PAPR reduction.

• Archives of Craniofacial Surgery
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• v.15 no.2
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• pp.53-58
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• 2014

Background: Maxillomandibular fixation (MMF) is usually used to treat double mandibular fractures. However, advancements in reduction and fixation techniques may allow recovery of the premorbid dental arch and occlusion without the use of MMF. We investigated whether anatomical reduction and microplate fixation without MMF could provide secure immobilization and correct occlusion in double mandibular fractures. Methods: Thirty-four patients with double mandibular fractures were treated with open reduction and internal fixation without MMF. Both fracture sites were surgically treated. For bony fixations, we used microplates with or without wire. After reduction, each fracture site was fixed at two or three points to maintain anatomical alignment of the mandible. Interdental wiring was used to reduce the fracture at the superior border and to enhance stability for 6 weeks. Mouth opening was permitted immediately. Results: No major complications were observed, including infection, plate exposure, non-union, or significant malocclusion. Five patients experienced minor complications, among whom the only one patient experienced a persistant but mild malocclusion with no need for additional management. Conclusion: This study showed that double mandibular fractures correction with two-or three-point fixation without MMF simplified the surgical procedure, increased patient comfort, and reduced complications, due to good stability and excellent adaptation.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.227-232
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• 2019

MRI examination for patients with metal objects has in poor image quality. Metallic implants can result in poor image because magnetic susceptibility causes signal loss and distortion and makes poor imaging, which is called magnetic susceptibility artifact or metal artifact. There are several approaches to reduce metal artifacts. In this study, we study the reduction of metal artifact by VAT and SEMAC techniques. A metal implant used for orthopedic surgery was attached to the phatom and the distortion caused by the artifact was measured under T1WI and T2WI protocols. Several techniques of VAT only and VAT and SEMAC for the reduction of metal artifact were compared. The metal artifact showed a reduction of at least 8% to a maximum of 26% in the VAT-SEMAC. The VAT-SEMAC technique can be applied to patients with orthopedic implants to improve image quality. If scan time and image quality are simultaneously considered in VAT-SEMAC technique, metal artifact will be reduced in clinical practice.

• Restorative Dentistry and Endodontics
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• v.43 no.4
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• pp.46.1-46.10
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• 2018

Objectives: This study was to evaluate the antibacterial effect of different instrumentation and irrigation techniques using confocal laser scanning microscopy (CLSM) after root canal inoculation with Enterococcus faecalis (E. faecalis). Materials and Methods: Mesiobuccal and mesiolingual canals of extracted mandibular molars were apically enlarged up to a size 25 hand K-file, then autoclaved and inoculated with E. faecalis. The samples were randomly divided into 4 main groups according to the system of instrumentation and irrigation: an XP-endo Shaper (XPS) combined with conventional irrigation (XPS/C) or an XP-endo Finisher (XPF) (XPS/XPF), and iRaCe combined with conventional irrigation (iRaCe/C) or combined with an XPF (iRaCe/XPF). A middle-third sample was taken from each group, and then the bacterial reduction was evaluated using CLSM at a depth of $50{\mu}m$ inside the dentinal tubules. The ratio of red fluorescence (dead cells) to green-and-red fluorescence (live and dead cells) represented the percentage of bacterial reduction. The data were then statistically analyzed using the Kruskal-Wallis test for comparisons across the groups and the Dunn test was used for pairwise comparisons. Results: The instrumentation and irrigation techniques had a significant effect on bacterial reduction (p < 0.05). The iRaCe/XPF group showed the strongest effect, followed by the XPS/XPF and XPS/C group, while the iRaCe/C group had the weakest effect. Conclusions: Combining iRaCe with XPF improved its bacterial reduction effect, while combining XPS with XPF did not yield a significant improvement in its ability to reduce bacteria at a depth of $50{\mu}m$ in the dentinal tubules.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.5
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• pp.357-363
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• 2003

There have been lots of studies on noise transmission analysis and noise reduction In ducts. In order to reduce the noise transmission in ducts. active noise cancellation techniques have often been employed and a rotation shaft with blades has sometimes been suggested. These Ideas were not successfully commercialized because of the limitation of real life such as size or application difficulties. This study investigated how a rotational shaft with blades could reduce the noise transmission in a duct. To do so, an assembly of the shaft and the $haft housing was built In the middle of a duct. and the clearance between the blades and the housing was 0.2 mm. The noise reduction was experimentally evaluated with respect to the number of blades. the rotation speed, and the rotation or stop. This paper showed that the noise reduction resulted in about 14∼19 dBA regardless of the three test conditions only If the blades always blocked the duct. And. the noise reduction increased due to the higher number of blades and the lower speed of the shaft.

• Journal of the Korean Ceramic Society
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• v.55 no.4
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• pp.381-391
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• 2018

In this work, photocatalytic $CO_2$ reduction over a CdSe-graphene-$TiO_2$ nanocomposite has been studied. The obtained material was successfully fabricated via ultrasonic technique. The physical properties of the as-synthesized materials were characterized by some physical techniques. The $TiO_2$ and CdSe dispersed graphene nanocomposite showed excellent results of strong reduction rates of $CO_2$ compared to the results of bare $TiO_2$ and binary CdSe-graphene. An outstanding point of the combination of CdSe-$TiO_2$ and graphene appeared in the form of great photocatalytic reduction capability of $CO_2$. The photocatalytic activity of the asfabricated composite was tested by surveying for the photoreduction of $CO_2$ to alcohol under UV and visible light irradiation, and the obtained results imply that the as-prepared CdSe-graphene-$TiO_2$ nanocomposite is promising to become a potential candidate for the photocatalytic $CO_2$ reduction.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup1
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• pp.159-164
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• 2001

Reduction cranioplasty is one of the treatment modality among many treatment options for macrocephaly with hydrocephalus. The most previous techniques of reduction cranioplasty have some disadvantages such as difficult airway maintenance, pressure sore due to modified prone position, severe venous infarct due to obstruction of venous blood flow and large amount of bleeding from the dissection of superior sagittal sinus to obtain bone fragment needed. A 28-month-old girl had extreme macrocephaly. She couldn't control head rotation and keep sitting position. The operation was performed at supine position with adequate exposure of entire calvarium and the hinge was made in occipital bone fragment that covered posterior part of superior sagittal sinus. Bleeding volume and the other complications were decreased and acceptable reduction was achieved with this method.

• Journal of Wellbeing Management and Applied Psychology
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• v.5 no.2
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• pp.21-27
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• 2022

Purpose: This study is about photocatalytic technology and plasma oxidation-reduction technology. To the main cause of exposure to odor pollution, two deodorization techniques were applied to develop a module with higher removal efficiency and ozone reduction effect. Research design, data and methodology: A composite module was constructed by arranging two types of dry deodorization equipment (catalyst, adsorbent) in one module. This method was designed to increase the responsiveness to the components of complex odors and the environment. standard, unity, two types of oxidizing photo-catalyst technology and plasma dry deodorization device installed in one module to increase the potential by reduction to 76% of ozone, 100%, and 82%. Results: The complex odor disposal efficiency was 92%. Ammonia was processed with 50% hydrogen sulfide and 100% hydrogen sulfide, and ozone was 0.01ppm, achieving a target value of 0.07ppm or less. The combined odor showed a disposal efficiency of 93%, ammonia was 82% and hydrogen sulfide was 100% processed, and ozone achieved a target value of 0.07 ppm or less. Conclusions: Ozone removal efficiency was 76% by increasing Oxidation-Reduction Reaction(ORR). The H2S removal efficiency of the deodorizer was higher than that of the biofilter system currently used in sewage disposal plants.