• Journal of the Korean GEO-environmental Society
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• v.15 no.6
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• pp.49-56
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• 2014

The stability of tunnel construction depends entirely on the characteristics of the soil strength. If the soil strength is weak, collapse of tunnel occurs frequently under construction. In general, it copes with collapse by conducting half section excavation or reinforcement in advance under these conditions. Nevertheless, it can be collapsed under upper section excavation in the weathered fracture zone and it can be recovered through the application of reinforcement. As it has a bad influence on the upper section in case of upheaveal of tunnel bottom, it can be adversely affected on the overall stability of the tunnel. Thus, an in-depth review of reinforcement is needed in poor bottom ground. As the practices that has a bad affect on the stability of the tunnel due to upheaveal of tunnel bottom is increasing, research is needed for applicable standards for reinforcement. In this paper, it were investigated at actual field cases of upheaveal of bottom ground and characteristics of behavior and reinforcement measures were analyzed.

• Journal of Internet of Things and Convergence
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• v.6 no.2
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• pp.93-100
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• 2020

Although various home services are developed as increasing the number of home devices with wire and wireless connection, privacy infringement and private information leakage are occurred by unauthorized remote connection. It is almost caused by without of device authentication and protection of transmission data. In this paper, the devices' secret value are stored in a safe memory of a smartphone. A smartphone processes device authentication. In order to prevent leakage of a device's password, a shadow password multiplied a password by the private key is stored in a device. It is proposed mutual authentication between a smartphone and a device, and session key agreement for devices using recovered passwords on SRP. The proposed protocol is resistant to eavesdropping, a reply attack, impersonation attack.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.58-61
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• 2018

In Korea, current medical technology is the highest level in the world. As a result, many doctors have specialized knowledge of various disorders or diseases, and are proceeding in a better way. With such high medical technology, it is possible to increase the probability of success of surgery to provide high reliability to patients. Rehabilitation is also a form of medical treatment that reduces the side effects that occur after surgery that is done for quick cure. However, the situation in this section is slightly different. There are moves to develop rehabilitation devices and operations, but most of them are now dependent on foreign technology. Rehabilitation therapy, which we commonly know, is dominated by behavior. However, it is also a kind of rehabilitation to find out how much the patient's symptoms are improved or recovered. In this paper, we have studied the development of a program by using the Deeplearning method in order to detect the problem of the food swallowing operation by the severity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.5
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• pp.822-832
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• 1994

DSC-HDTV image compression algorithm removes spatial, temporal, and amplitude redundancies of an image by using transform coding, motion-compensated predictive coding, and adaptive quantization, respectively. In this paper, leak processing method which is used to recover image quality quickly from scene change and transmission error and adaptive quantization using perceptual weighting factor obtained by HVS are proposed. Perceptual weighting factor is calculated by contrast sensitivity, spatio-temporal masking and frequency sensitivity. Adaptive quantization uses the perceptual weighting factor and global distortion level from buffer history state. Redundant bits according to adaptation of HVS are used for the next image coding. In the case of scene change, DFD using motion compensated predictive coding has high value, large bit rate and unstabilized buffer states since reconstructed image has large quantization noise. Thus, leak factor is set to 0 for scene change frame and leak factor to 15/16 for next frame, and global distortion level is calculated by using standard deviation. Experimental results show that image quality of the proposed method is recovered after several frames and then buffer status is stabilized.

• The Journal of the Acoustical Society of Korea
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• v.36 no.1
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• pp.39-48
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• 2017

CDMA (Code Division Multiple Access) is promising medium access control schemes for underwater acoustic sensor networks because of its robustness against frequency-selective fading and high frequency-reuse efficiency. In this paper, we design diversity schemes of underwater CDMA transceiver for the forward and reverse links. User data are multiplexed by Walsh code and a pseudo random noise code acquisition process is added for phase error correction before decoding the user data at the receiver. Then, the diversity reception using equal gain combining and maximal ratio combining is performed in order to minimize performance degradation caused by rich multipath fading of underwater acoustic channel. We evaluated the performance of diversity transceiver through lake experiment, which was performed at Lake Kyungcheon, Mungyeong city using two transmitters and two receivers placed 460 m apart at an average depth of 40 m. The lake experiment results show that user data are recovered with error-free in both of the forward and reverse links.

• Convergence Security Journal
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• v.16 no.6_1
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• pp.43-50
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• 2016

As North Korea has a sufficient ability to attack our society's vulnerable computer network, various large-scale cyber attacks are expected to be tried. North Korea's cyber military strength is known a world-class level. The number of its cyber agents is increasing consistently. Recently North Korea's cyber attack has been made regardless of trick and target. But up to now North Korea's cyber attack is more of an exploration than a real attack. Its purpose was to check how fast Korea found a problem and recovered from it. In future, cyber attack that damages substantially is highly probable. In case of an attack against national infrastructure like traffic, financial and energy services, the extent of the damage will be great beyond imagination. In this paper, characteristics of recent North Korea's cyber attack is addressed in depth and countermeasures such as the enactment of cyber terror prevention law, simulation training enforcement, private and public cooperation system construction, cyber security infrastructure expansion, etc. are proposed.

• STI Policy Review
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• v.3 no.2
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• pp.130-151
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• 2012

Fraunhofer was founded in 1949 and grew into Europe's largest application-oriented research organization. Fraunhofer currently employs over 20,000 members in Germany, is internationally networked, and manages an R&D budget of over 1,8 Billion Euros per year. An important step for Fraunhofer to become an integral component of the German innovation system was the introduction of the Fraunhofer Model of financing based on a performance-related system of financial management. The underlying model of the allocation and distribution of public funding to Fraunhofer that is subsequently allotted to specific research groups is one of the success factors of Fraunhofer. Fraunhofer is proud of its decentralized organizational model. Fraunhofer is comprised of 60 Institutes in Germany working in different fields, under one legal framework, and with a strong brand value. Every Fraunhofer Institute is affiliated with a German University and every institute director simultaneously holds a chair at the affiliated university. It is a challenge for the headquarter organization to balance the intended competition of individual Fraunhofer Institutes with complementarity cooperation in science among Fraunhofer-Institutes, especially when coming from different knowledge domains; however, this goal results in a significant advantage. The unique strengths of Fraunhofer offer system solutions in a world with increasingly complex R&D challenges. While growing to become the largest organization on Europe to focus on applied research it is the challenge to remain an agile organization that is flexible in organizational structure. Fraunhofer has reached a well-recognized position in the European innovation landscape. It is often referred to by science and governments as a role model for innovation policy and a key element of the latest successes in the German economy that has recovered quicker from the latest economic crisis than most other western economies. The paper explains Fraunhofer as an organizational paradigm and its underlying management model to elaborate on the challenges of managing a research organization. We wish to show how it is possible to transfer the management model and philosophy of Fraunhofer to innovation systems with different framework conditions and challenges. A universal conclusion may be drawn based on the description of Fraunhofer; however, changes in existing structures and innovation systems cannot be implemented over night.

• Journal of Hydrogen and New Energy
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• v.30 no.6
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• pp.490-498
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• 2019

The intermittent electric power supply of renewable energy can have extremely negative effect on power grid, so long-term and large-scale storage for energy released from renewable energy source is required for ensuring a stable supply of electric power. Power to gas which can convert and store the surplus electric power as hydrogen through water electrolysis is being actively studied in response to increasing supply of renewable energy. In this paper, we proposed the novel concept of hydrogen liquefaction process combined with pre-cooling process using the liquid air. It is that hydrogen converted from surplus electric power of renewable energy was liquefied through the hydrogen liquefaction process and vaporization heat of liquid hydrogen was conversely recovered to liquid air from ambient air. Moreover, Comparisons of specific energy consumption (kWh/kg) saved for using the liquid air pre-cooling was quantitatively conducted through the performance analysis. Consequently, about 12% of specific energy consumption of hydrogen liquefaction process was reduced with introducing liquid air for pre-cooling and optimal design point of helium Brayton cycle was identified by sensitivity analysis on change of compression/expansion ratio.

• Archives of Craniofacial Surgery
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• v.19 no.3
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• pp.175-180
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• 2018

Background: The facial bone has a complex structure compared to other bones, and various types of fractures can occur due to its characteristics. Among them, in comminuted fractures of anterior maxillary wall, multiple depressed and impacted bony segments cannot be reduced easily when performing internal fixation using plates and screws or wires, and inadequate restoration leads to a range of complications. This paper introduces an alternative technique using a resorbable mesh with fibrin glue to restore comminuted fractures of anterior maxillary wall. Methods: Thirteen patients were diagnosed with comminuted fractures of anterior maxillary wall between March 2017 and February 2018 in the authors' hospital. All patients with comminuted fractures of anterior maxillary wall underwent restoration using resorbable mesh with fibrin glue. The patients' demographics, causes of facial trauma, mean operation time, length of hospital stay, follow-up period, and complications were recorded. Results: No major complications and only one hypoesthesia of the skin area was noted. Three months after surgery, the hypoesthesia recovered completely. After surgery (mean, 3.9 months; range, 2-12 months), computed tomography showed that the bone fragments in all patients were fixed successfully in their anatomical places. Conclusion: In comminuted fractures of anterior maxillary wall, the use of a resorbable mesh with fibrin glue can be an advantageous and effective method for a successful restoration without complications.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.5
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• pp.885-896
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• 2014

The files in computer storages can be deleted due to unexpected failures or accidents. Some malicious users often delete data by himself for anti-forensics. If deleted files are associated with crimes or important documents in business, they should be recovered and the recovery tool is necessary. The recovery methods and tools for some filesystems such as NTFS, FAT, and EXT have been developed actively. However, there has not been any researches for recovering deleted files in XFS filesystem applied to NAS or CCTV. In addition, since the current related tools are based on the traditional signature detection methods, they have low recovery rates. Therefore, this paper suggests the recovery methods for deleted files based on metadata and signature detection in XFS filesystem, and verifies the results by conducting experiment in real environment.