• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.10a
• /
• pp.907-909
• /
• 2009

In this paper, the dependence of threshold voltage on the gate oxide thickness, which it mostly influenced on short channel effects in fabrication of FinFET, has been investigated. The transport model based on three dimensional Possion's equation has been used to analyze influence on gate oxide thickness. The gate oxide thickness is the most important factor to influence on the threshold voltage in nano structure FinFET. The potential distributions of this model are compared with those of three dimensional numerical simulation to verify this model. As a result, since potential model presented in this paper is good agreement with hree dimensional numerical model, the threshold voltage characteristics have been considered according to the gate oxide thickness of FinFET.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.31 no.6
• /
• pp.359-366
• /
• 2018

Social infrastructure facilities that have been under construction since the country's high-growth period are undergoing rapid aging, and safety assessments of large structures such as bridge tunnels, which can be directly linked to large-scale casualties in the event of an accident, are necessary. Wireless smart sensor networks that improve SHM(Structural Health Monitoring) based on existing wire sensors are difficult to construct economical and efficient system due to short signal reach. The LPWAN, Low Power Wide Area Network, is becoming popular with the Internet of Things and it is possible to construct economical and efficient SHM by applying it to structural health monitoring. This study examines the applicability of LoRa LPWAN to structural health monitoring and proposes a channel usage pre-planning based LoRa network operation method that can efficiently utilize bandwidth while resolving conflicts between channels caused by using license - exempt communication band.

• Journal of the Korea Convergence Society
• /
• v.10 no.8
• /
• pp.137-144
• /
• 2019

This paper deals with the longitudinal study on the supply & demand-side diversity of digital media service. The purpose of this study is to measure the diversity of contents supply and demand-side of digital media platform providers by longitudinal data and discuss the implication. In the approval and re-authorization of pay-TV broadcasters, there were attempts to measure diversity indicators as items to evaluate the publicness and public interest of broadcasting, but they are mainly limited to the method of measuring diversity in the short-term supply side. Thus researcher wants to confirm the evaluation of two aspects through this study. First, researcher proposes a demand-side measurement methodology that utilizes actual audience data from users, and second, a longitudinal evaluation methodology that evaluates long-term trends of diversity change. Researcher has secured the actual supply and demand data of the platform player and confirmed trends of longitudinal diversification indexing for 50 months from 2012 to 2017. Through this research, researcher expects that the supply and demand-side and the longitudinal diversity evaluation will be utilized in a balanced way of publicness and public interest evaluation of broadcasting.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.3
• /
• pp.465-470
• /
• 2021

A robust speech recognition technology is required that does not degrade the performance of speech recognition and the quality of the speech when speech recognition is performed in an actual environment of the speech mixed with noise. With the development of such speech recognition technology, it is necessary to develop an application that achieves stable and high speech recognition rate even in a noisy environment similar to the human speech spectrum. Therefore, this paper proposes a speech enhancement algorithm that processes a noise suppression based on the MMSA-STSA estimation algorithm, which is a short-time spectral amplitude method based on the error of the least mean square. This algorithm is an effective nonlinear speech enhancement algorithm based on a single channel input and has high noise suppression performance. Moreover this algorithm is a technique that reduces the amount of distortion of the speech based on the statistical model of the speech. In this experiment, in order to verify the effectiveness of the MMSA-STSA estimation algorithm, the effectiveness of the proposed algorithm is verified by comparing the input speech waveform and the output speech waveform.

• Journal of Gastric Cancer
• /
• v.21 no.2
• /
• pp.132-141
• /
• 2021

Purpose: Intracorporeal esophagojejunostomy during reduced-port gastrectomy for proximal gastric cancer is a technically challenging technique. No study has yet reported a robotic technique for anastomosis. Therefore, to address this gap, we describe our reduced-port technique and the short-term outcomes of intracorporeal esophagojejunostomy. Materials and Methods: We conducted a retrospective review of patients who underwent a totally robotic reduced-port total or proximal gastrectomy between August 2016 and March 2020. We used an infra-umbilical Single-Site^® port with two additional ports on both sides of the abdomen. To transect the esophagus, a 45-mm endolinear stapler was inserted via the right abdominal port. The common channel of the esophagojejunostomy was created between the apertures in the esophagus and proximal jejunum using a 45-mm linear stapler. The entry hole was closed with a 45-mm linear stapler or robot-sewn continuous suture. All anastomoses were performed without the aid of an assistant or placement of stay sutures. Results: Among the 40 patients, there were no conversions to open, laparoscopic, or conventional 5-port robotic surgery. The median operation time and blood loss were 254 min and 50 mL, respectively. The median number of retrieved lymph nodes was 40.5. The median time to first flatus, soft diet intake, and length of hospital stay were 3, 5, and 7 days, respectively. Three (7.5%) major complications, including two anastomosis-related complications and a case of small bowel obstruction, were treated with an endoscopic procedure and re-operation, respectively. No mortality occurred during the study period. Conclusions: Intracorporeal esophagojejunostomy during reduced-port gastrectomy can be safely performed and is feasible with acceptable surgical outcomes.

• Journal of the Economic Geographical Society of Korea
• /
• v.25 no.1
• /
• pp.61-86
• /
• 2022

This paper analyzes the technology transfer mechanism of companies clustered in a specific economic space from the perspective of absorptive capacity, taking the Daegu automotive parts industry as an example. According to the analysis results, The absorptive capacity of a company was found to be positively related to the supplier, channel, method, and institutional interaction of technology transfer. Low absorptive capacity limits technology transfer by reducing companies' technology search capabilities, while high absorptive capacity gives companies access to technology search and various technology transfer opportunities through formal and informal channels. These results suggest that, in the short term, it is necessary to supplement the search capabilities of companies through preemptive visiting services of local intermediaries for the vitalization of regional technology transfer, while in the long term, a policy approach focusing on enhancing the absorptive capacity of local companies is required. For effective implementation of these policies, a multi-layered governance approach corresponding to each level of companies' absorptive capacities is required in establishing an interface structure that promotes linkage between institutional actors.

• Ocean and Polar Research
• /
• v.44 no.1
• /
• pp.13-27
• /
• 2022

The Yeongsan River estuary was altered by a sea dike built in 1981 and the sluice gates in the dike were extended recently in 2014. The construction has caused changes in water properties and hydrodynamics and also produced disturbances including hypoxia and algal blooms. We analyzed the water quality and chlorophyll-a data (2009-2018) collected seasonally at 3 stations (Sts. 1-3) along the channel of the estuary by the Marine Environmental Monitoring System. Variations in water quality and chlorophyll-a (an index of phytoplankton biomass) were examined and their stressors were also identified by statistics including correlation and multivariate principal component analyses (PCA). The water quality was mainly affected by freshwater discharge from the dike. Salinity, nutrients and chlorophyll-a were especially affected by the discharge and the effect enhanced during summer and at the upper region near the sea dike decreasing downstream. Three factors were extracted for each station in the PCA accounting for 66.07-72.42% of the variations. The first was an external factor associated with freshwater discharge and the second and third were seasonal or biological factors. The results indicate that the water quality is more affected by short-termed and episodic events such as freshwater discharge than seasonal events and the influence of freshwater discharge on water quality is more extensive than that previously reported. This suggests that the boundary of the estuary should be extended to take into account the findings of this study and a management strategy linked to the freshwater zone is required to manage the integrity and water quality of the Yeongsan River estuary.

• Journal of the Korea Society for Simulation
• /
• v.31 no.4
• /
• pp.11-22
• /
• 2022

Unlike a short-range, a long-range underwater acoustic communication(UWAC) uses low frequency signal and deep sound channel to minimize propagation loss. In this case, even though communication signals are modulated using a covert transmission technique such as spread spectrum, it is hard to conceal the existence of the signals. The unconcealed communication signal can be utilized as active sonar signal by enemy and presence of underwater vehicles may be exposed to the interceptor. Since it is very important to maintain stealthiness for underwater vehicles, the detection probability of friendly underwater vehicles should be considered when interceptor utilizes our long-range UWAC signal. In this paper, we modeled a long-range UWAC environment for analyzing the detection performance of underwater vehicles and proposed the region of interest(ROI) setup method and the measurement of detection performance. By computer simulations, we yielded parameters, analyzed the detection probability and the detection performance in ROI. The analysis results showed that the proposed detection performance analysis method for underwater vehicles could play an important role in the operation of long-range UWAC equipment.

• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.6_3
• /
• pp.1147-1154
• /
• 2022

Now that the development of autonomous driving is progressing, LiDAR has become an indispensable element. However, LiDAR is a device that uses lasers, and laser side effects may occur. One of them is the much-talked-about eye-safety, and developers have been satisfying this through laser characteristics and operation methods. But eye-safety is just one of the problems lasers pose. For example, irradiating a laser with a specific energy level or higher in a dusty environment can cause deterioration of the dust particles, leading to a sudden explosion. For this reason, the dust ignition proof regulations clearly state that "a source with a pulse period of less than 5 seconds is considered a continuous light source, and the average energy does not exceed 5 mJ/mm 2 or 35 mW" [2]. Energy of output optical power is limited by the law. In this way, the manufacturer cannot define the usage environment of the LiDAR, and the development of a LiDAR that can be used in such an environment can increase the ripple effect in terms of use in application fields using the LiDAR. In this paper, we develop a LiDAR with low optical power that can be used in environments where high power lasers can cause problems, evaluate its performance. Also, we discuss and present one of the directions for the development of LiDAR with laser power limited by dust ignition proof regulations.

• Korean Journal of Applied Biomechanics
• /
• v.33 no.1
• /
• pp.10-16
• /
• 2023

Objective: The purpose of this was to find out the muscle activity of the quadriceps femoris by gender when sitting on a chair while performing stairs gait (US; Up-stairs, DS; Down-stairs). Method: 13 male subjects (age: 22.00 ± 1.68 yrs, height: 174.85 ± 6.10 cm, weight: 68.15 ± 9.83 kg) and 15 female subjects (age: 21.17 ± 1.58 yrs, height: 168.20 ± 5.55 cm, weight: 55.73 ± 6.94 kg) participated in this study. The study used wireless three channel EMG. Results: In this study, there was no gender difference in quadriceps femoris activity during the US and DS periods, and there was no significant difference between the male group before and after postural maintenance during the US and DS periods. The quadriceps muscle of the female group also did not show a significant difference before and after US sitting. However, the vastus medialis muscle activity during DS in the female group was significantly lower after application than before application of maintaining a sitting posture (p<.05). There was no interaction effect between the 15-minute sitting position application and gender. Conclusion: Our results demonstrate that sitting in a chair affects the transient functioning of the quadriceps muscle in women. Therefore, emphasize the need for active rest when sitting in a chair for long periods of time.