• Journal of Korean Neurosurgical Society
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• 제46권4호
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• pp.378-384
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• 2009

Objective : In order to establish the role of Gamma Knife radiosurgery (GKS) in large intracranial arteriovenous malformations (AVMs), we analyzed clinical characteristics, radiological features, and radiosurgical outcomes. Methods : Between March 1992 and March 2005, 28 of 33 patients with large AVMs (> $10\;cm^3$ in nidus-volume) who were treated with GKS underwent single session radiosurgery (RS), and the other 5 patients underwent staged volumetric RS. Retrospectively collected data were available in 23 cases. We analyzed treatment outcomes in each subdivided groups and according to the AVM sizes. We compared the estimated volume, defined as primarily estimated nidus volume using MR images, with real target volume after excluding draining veins and feeding arteries embedded into the nidus. Results : Regarding those patients who underwent single session RS, 44.4% (8/18) had complete obliteration; regarding staged volumetric RS, the obliteration rate was 40% (2/5). The complete obliteration rate was 60% (6/10) in the smaller nidus group ($10-15\;cm^3$ size), and 25% (2/8) in the larger nidus group (over $15\;cm^3$ size). One case of cerebral edema and two cases (8.7%) of hemorrhage were seen during the latent period. The mean real target volume for 18 single sessions of RS was $17.1\;cm^3$ ($10.1-38.4\;cm^3$), in contrast with the mean estimated volume of $20.9\;cm^3$ ($12.0-45.0\;cm^3$). Conclusion : The radiosurgical treatment outcomes of large AVMs are generally poor. However, we presume that the recent development in planning software and imaging devices aid more accurate measurement of the nidus volume, therefore improving the treatment outcome.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제19권8호
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• pp.1965-1972
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• 2015

The Missile Flight Test Launch Control System is to operate in conjunction with the Fire Control System during flight test to guided weapons. Also, this is a system for the test control and situation monitoring depending on the type of guided weapons and testing purposes. Message structure, communication protocols, such as data types for interworking with the fire control system and the Missile Flight Test Launch Control System are defined in the Launch Control ICD(Interface Control Document). ICD are composed differently of each guided weapons system and each test object. Previously, in order to interwork with the Fire Control System, the interlocking software was developed, which had a variety of problems. Therefore, we developed a new parsing algorithm in order to recognize the variety of Launch Control ICD and verified that the algorithm operates normally by checking transmitting and receiving various message in conjunction with the fire control system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제41권10호
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• pp.805-812
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• 2013

The operational flight program(OFP) which has the functions of I/O processing with avionics, flight control logic calculation, fault diagnosis and redundancy mode is embedded in the flight control computer of Smart UAV. The OFP was developed in the environment of PowerPC 755 processor and VxWorks 5.5 real-time operating system. The OFP consists of memory access module, device I/O signal processing module and flight control logic module, and each module was designed to hierarchical structure. Memory access and signal processing modules were verified from bench test, and flight control logic module was verified from hardware-in-the-loop simulation(HILS) test, ground integration test, tethered test and flight test. This paper describes development environment, software structure, verification and management method of the OFP.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제21권5호
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• pp.893-898
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• 2017

A TDC(Time-to-Digital Converter) of counter-type is designed by $0.18{\mu}mCMOS$process and the supply voltage is 1.5 volts. The converted error of maximum $T_{CK}$ is occurred by the time difference between the start signal and the clock when the period of clock is $T_{CK}$ in the conventional TDC. And the converted error of -$T_{CK}$ is occurred by the time difference between the stop signal and the clock. However in order to compensate the disadvantage of the conventional TDC the clock is generated within the TDC circuit and the clock is synchronized with the start and stop signals. In the designed TDC circuit the conversion error is not occurred by the difference between the start signal and the click and the magnitude of conversion error is reduced (1/2)$T_{CK}$ by the time difference between the stop signal and the clock.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제17권7호
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• pp.1740-1746
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• 2013

Augmentative and alternative communication(AAC) is a communication tool for those with impairments or restrictions on the production or comprehension of spoken language. Traditional AAC has used a portable board with pictures and texts with which disabled person could be supported by it. Currently, smart phone based AAC researches and developments are actively studying. With emerging concepts of context-aware computing, the mobile devices can provide mobile users with timely information and location based services. We proposed a adjustable AAC system for disabled people of which has variable layouts and selectable items. We also implemented context-ware application for AAC systems including time, location and click count informations on smart phone. The system can adaptively change its layout and select AAC items depending on various situation of disabled persons.

• Journal of KIISE:Software and Applications
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• 제31권10호
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• pp.1356-1363
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• 2004

We propose Tangible Media Control System (TMCS), which allows users to manipulate media contents with physical objects in an intuitive way. Currently, most people access digital media contents by exploiting GUI. However, It provides limited manipulations of the media contents. The proposed system, instead of mouse and keyboard, adopts two types of tangible objects, i.e RFID-enabled object and tracker-embedded object. The TMCS enables users to easily access and control digital media contents with the tangible objects. In addition, it supports an interactive media controller which users can synthesize media contents and generate new media contents according to users' taste. It also offers personalized contents, which is suitable for users' preferences, by exploiting context such as user's profile and situational information. Therefore. the proposed system can be applied to various interactive applications such as multimedia education, entertainment and multimedia editor.

• Journal of KIISE:Software and Applications
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• 제27권7호
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• pp.759-768
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• 2000

The ZG-machine is a space-efficient G-machine, which exploits a simple encoding method, called tag-forwarding, to compress the heap structure of graphs. Experiments on the ZG-machine without garbage collection shows that the ZG-machine saves 30% of heap space and the run-time overhead is no more than 6% than the G-machine. This paper presents the results of further experiments on the ZG-machine with the garbage collector. As a result, the heap-residency of the ZG-machine decreases by 34% on average although the run-time increases by 34% compared to the G-machine. The high rate of the run-time overhead of the ZG-machine is incurred by the garbage collector. However, when the heap size is 7 times the heap-residency, the run-time overhead of the ZG-machine is no more than 12% compared to the G-machine. With the aspect of reduced heap-residency, the ZG-machine may be useful in memory-restricted environments such as embedded systems. Also, with the development of a more efficient garbage collector, the run-time is expected to decrease significantly.

• KIPS Transactions on Software and Data Engineering
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• 제5권1호
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• pp.43-50
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• 2016

This paper introduces an appearance-based facial expression recognition method using ASM landmarks which is used to acquire a detailed face region. In particular, EHMM-based algorithm and SVM classifier with histogram feature are employed to appearance-based facial expression recognition, and performance evaluation of proposed method was performed with CK and JAFFE facial expression database. In addition, performance comparison was achieved through comparison with distance-based face normalization method and a geometric feature-based facial expression approach which employed geometrical features of ASM landmarks and SVM algorithm. As a result, the proposed method using ASM-based face normalization showed performance improvements of 6.39% and 7.98% compared to previous distance-based face normalization method for CK database and JAFFE database, respectively. Also, the proposed method showed higher performance compared to geometric feature-based facial expression approach, and we confirmed an effectiveness of proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제34권11B호
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• pp.1151-1168
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• 2009

Improving packet loss does not necessarily coincide with the improvement in user perceivable QoS because each frame carries different degree of importance. We propose Significance-aware packet scheduling (SAPS) to maximize user perceivable QoS. SAPS carries out two fundamental issues of packet scheduling: "What to transmit" and "When to transmit?" To adapt to the available bandwidth, it is necessarily to transmit the subset of the data packets if the entire set of packets can not be transmitted. "Packet Significance" quantifies the importance of the frame by elaborately incorporating frames' dependency. Greedy approach is used in selecting packets and transmission schedule is determined based on the Packet Significance. The proposed scheme is tested using publicly available MPEG-4 video clips. Decoding engine is embedded in the simulation software and user perceivable QoS is exposeed in termstermiSNR. Throughout the simulation based experiment, the performance of the proposed scheme is compared two other schemes: Size-based packet scheduling and Bit-rate based best effort packet scheduling. SAPS successfully incorporates the semantics of a packet and improves user perceivable QoS significantly. It successfully provides unequal protection to more important packets.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제33권9C호
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• pp.712-719
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• 2008

Temporal error concealment indicates the algorithm that restores the lost video data using temporal correlation between previous frame and current frame with lost data. It can be categorized into the methods of block-based and pixel-based concealment. The proposed method in this paper is for pixel-based temporal error concealment using affine transform. It outperforms especially when the object or background in lost block has geometric transform which can be modeled using affine transform, that is, rotation, magnification, reduction, etc. Furthermore, in order to maintain good performance even though one or more motion vector represents the motion of different objects, we defines a cost function. According to cost from the cost function, the proposed method adopts affine error concealment adaptively. Simulation results show that the proposed method yields better performance up to 1.9 dB than the method embedded in reference software of H.264/AVC.