• The Journal of Korea Robotics Society
• /
• v.3 no.1
• /
• pp.58-67
• /
• 2008

This study developed a novel augmented reality interface for minimally invasive surgery. The augmented reality technique can alleviate the sensory feedback problem inherent to laparoscopic surgery. An augmented reality system merges real laparoscope image and reconstructed 3D patient model based on diagnostic medical image such as CT, MRI data. By using reconstructed 3D patient model, AR interface could express structure of patient body that is invisible outside visual field of laparoscope. Therefore, an augmented reality system improved sight information of limited laparoscope. In our augmented reality system, the laparoscopic view is located at the center of a wide-angle concave screen and reconstructed 3D patient model is displayed outside the laparoscope. By using a joystick, the laparoscopic view and the reconstructed 3D patient model view are changed concurrently. With our augmented reality system, the surgeon can see the peritoneal cavity from a wide angle of view, without having to move the laparoscope. Since the concave screen serves immersive environments, the surgeon can feel as if she is in the patient body. For these reasons, a surgeon can recognize easily depth information about inner parts of patient and position information of surgical instruments without laparoscope motion. It is possible for surgeon to manipulate surgical instruments more exact and fast. Therefore immersive augmented reality interface for minimally invasive surgery will reduce bodily, environmental load of a surgeon and increase efficiency of MIS.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.5
• /
• pp.355-364
• /
• 2002

The goal of this research is to reduce noise level of an outdoor unit of air conditioner by changing its dynamic characteristics using SDM (structural dynamics modification) technique. At first, the emitting noise was measured and analyzed. The measurement records show the most critical frequency components which influences on the noise level. Then it was tried to move the natural frequencies outside the critical frequency region by SDM. Since it is very difficult to get a reliable FE model of air conditioner, experimentally measured frequency response functions were used to derive sensitivities that are very important to obtain design changes. The positions of modification and the thickness of modifying structures were determined to improve the dynamic characteristics of air conditioner. The recommended design guideline to move its natural frequencies outside the targeting frequency range was obtained. Then in order to prove its effectiveness, the changed design was experimentally tested and found that the SDM result is very effective to reduce not only its vibration but also its emitting noise.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.4
• /
• pp.113-120
• /
• 2023

Smart farms are steadily increasing in research to minimize labor, energy, and quantity put into crops as IoT technology and artificial intelligence technology are combined. However, research on efficiently managing crop growth information in smart farms has been insufficient to date. In this paper, we propose a management technique that can efficiently monitor crop growth information by applying autonomous sensors to smart farms. The proposed technique focuses on collecting crop growth information through autonomous sensors and then recycling the growth information to crop cultivation. In particular, the proposed technique allocates crop growth information to one slot and then weights each crop to perform load balancing, minimizing interference between crop growth information. In addition, when processing crop growth information in four stages (sensing detection stage, sensing transmission stage, application processing stage, data management stage, etc.), the proposed technique computerizes important crop management points in real time, so an immediate warning system works outside of the management criteria. As a result of the performance evaluation, the accuracy of the autonomous sensor was improved by 22.9% on average compared to the existing technique, and the efficiency was improved by 16.4% on average compared to the existing technique.

• Journal of the Korea Computer Industry Society
• /
• v.5 no.1
• /
• pp.39-48
• /
• 2004

An IP address shortage problem is happening with a rapid propagation of the Internet and demands about a new IP address. Address translation technology as NAT is becoming use widely in order to solve these problems. NAT is an very useful If address translation technique that allows two connected networks to use different and incompatible IP address schemes. Rut it is difficult to use NAT particularly for applications that embeded IP addresses in data payloads or encrypted IP packet to guarantee End-to-End Security such as IPSec. In addition to rewiting the source/destination IP address in the packet, NAT must modify IP checksum every time, which could lead to considerablely performance decrease of the overall system in the process of address translation. RSIP is an alternative to solve these disadvantages and address shortage problems of NAT. Both NAT and RSIP divide networks into inside and outside addressing realms. NAT translates addresses between internal network and external network, but RSIP uses a borrowed external address for outside communications. RSIP server assigns a routable, public address to an RSIP client temporaily to communicate with public network outside the private network. In this paper, I will analyze NAT and RSIP gateway system, and then I will propose the Linux-based RSIP gateway for more efficient IP Address Translation in Intranet environments based on RSIP standard of IETF.

• Journal of the Korean Society of Safety
• /
• v.27 no.1
• /
• pp.7-13
• /
• 2012

This paper describes the diagnosis techniques using UV images taken in the field under energized condition of power equipments in order to figure out and analyze the abnormal states on the terminals of power equipments. To classify the features of the terminals, the counted No. of the corona generated at the terminals is defined. According to the result detected, the No. of corona detected on the power equipments installed inside a building is less than that installed outside a building, and it strongly depends on the environment and installed condition. Thus, the environmental condition needs enhanced, and stable operation by the periodic inspection under energized condition of the power equipments is required. Especially, the event counting technique using UV camera is useful for the power equipments apart more than 20 m to apply, and there can be an error due to the features of the sensing techniques when the distance between the user and the objects is close less than 15 m. Therefore, the experimental result shows that event counting technique is employed in the case of the distance more than 15 m. The electrical safety can be ensured by using the UV detection technique and the criteria.

• Journal of Korea Spatial Information System Society
• /
• v.9 no.1
• /
• pp.31-43
• /
• 2007

Sensor data have the characteristics such as numerous and continuous data. Therefore, it is required to develop an index which could retrieve a specific sensor data efficiently from numerous sensed data. The index should have an efficient delete operation for the past data to support the data archiving. In this paper, we have proposed and implemented an index splitting technique to support the sensor data archiving. These splitted indexes compose of a virtual index (that is, index management component), which is shown as single tree from outside. Experimental results show that in the case of 100,000 insert operations the splitted index performs 8% better than the traditional TB-tree maximumly. And the splitted index outperforms TB-tree with retrieving queries when the region of query is small and the size of time domain is large.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.35 no.1
• /
• pp.61-67
• /
• 2015

Recently, the initiation of outside diameter stress corrosion cracking (ODSCC) at the tube support plate region of domestic steam generators (SG) with Alloy600 HTMA tubes has been increasing. As a result, SGs with Alloy600 HTMA tubes must be replaced early or are scheduled to be replaced prior to their designed lifetime. ODSCC is one of the biggest threats to the integrity of SG tubes. Therefore, the accurate evaluation of tube integrity to determine ODSCC is needed. Eddy current testing (ECT) is conducted periodically, and its results could be input as parameters for evaluating the integrity of SG tubes. The reliability of an ECT inspection system depends on the performance of the inspection technique and abilty of the analyst. The detection probability and ECT sizing error of degradation are considered to be the performance indices of a nondestructive evaluation (NDE) system. This paper introduces an optimized evaluation method for ECT, as well as the sizing error, including the analyst performance. This study was based on the results of a round robin program in which 10 inspection analysts from 5 different companies participated. The analysis of ECT sizing results was performed using a linear regression model relating the true defect size data to the measured ECT size data.

• Journal of KIISE
• /
• v.44 no.4
• /
• pp.352-362
• /
• 2017

This paper analyzes security threats in Security Enhanced (SE) Android and proposes a new technique to efficiently protect application data including private information on rooted Android phones. On an unrooted device, application data can be accessed by the application itself according to the access control models. However, on a rooted device, a root-privileged shell can disable part or all of the access control model enforcement procedures. Therefore, a root-privileged shell can directly access sensitive data of other applications, and a malicious application can leak the data of other applications outside the device. To address this problem, the proposed technique allows only some specific processes to access to the data of other applications including private information by modifying the existing SEAndroid Linux Security Module (LSM) Hook function. Also, a new domain type of process is added to the target system to enforce stronger security rules. In addition, the proposed technique separates the directory type of a newly installed application and the directory type of previously installed applications. Experimental results show that the proposed technique can effectively protect the data of each application and incur performance overhead up to or less than 2 seconds.

• Journal of the Korean Arthroscopy Society
• /
• v.9 no.2
• /
• pp.222-231
• /
• 2005

Purpose: This article describes a double-bundle ACL reconstruction technique using a five-strand hamstring tendon autograft with conventional anteromedial bundle reconstruction and additional posterolateral bundle reconstruction. Operative technique: For the tibial tunnel, the conventional single tunnel technique is performed and for the femoral tunnel, the double tunnel technique is performed with the anteromedial and posterolateral bundle. After minimal notchplasty, the anteromedial femoral tunnel is prepared with leaving one milimeter of posterior femoral cortex within the over-the-top, which if positioned at the 11-o'clock orientation for the right knee or at the 1-o'clock position for the left knee. The posterolateral femoral tunnel that is located 5 to 7 mm superior to the inner margin of the lateral meniscus anterior horn at $90^{\circ}$ of flexion is prepared with tile outside-in technique using a 4.5 cannulated reamer. The graft material for the double bundle reconstruction is made of the conventional four-strand hamstring autograft in the anteromedial bundle and of a single-strand semitendinosus tendon in the posterolateral bundle. The anteromedial bundle is fixed with using a rigid fix system on the femoral side and the posterolateral bundle is fixed to tie with the miniplate from the outside femur. Then, with the knee in $10^{\circ}\;to\;20^{\circ}$ of flexion, a bioabsorbable screw is simultaneously applied to achieve tibial fixation with tensioning of both bundles. Conclusion: A double bundle reconstruction with five-strand hamstring autograft, which is designed with a favorable conventional anteromedial bundle and an additional posterolateral bundle to restore rotation stability, seems to be a very effective method for the treatment for ACL instabilities.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.6
• /
• pp.3280-3298
• /
• 2019

Vehicular ad-hoc networks (VANETs) have become increasingly significant in intelligent transportation systems, they play a great role in improving traffic safety and efficiency. In the deployment of intelligent VANETs, intelligent vehicles can efficiently exchange important or urgent traffic information and make driving decisions. Meanwhile, secure data communication and vehicle's identity privacy have been highlighted. To cope with these security issues, in this paper, we construct an efficient anonymous authentication scheme with secure communication in intelligent VANETs. Combing the ElGamal encryption technique with a modified Schnorr signature technique, the proposed scheme provides secure anonymous authentication process for encrypted message in the vehicle-to-infrastructure communication model, and achieves identity privacy, forward security, and reply attack resistance simultaneously. Moreover, except the trusted authority (TA), any outside entity cannot trace the real identity of an intelligent vehicle. The proposed scheme is designed on an identity-based system, which can remove the costs of establishing public key infrastructure (PKI) and certificates management. Compared with existing authentication schemes, the proposed scheme is much more practical in intelligent VANETs.