• 대한전자공학회논문지
• /
• 제27권12호
• /
• pp.1925-1932
• /
• 1990

In this paper, we consider the effect of diffraction due to the finite-sized aperture and propose the new correction method of errors in measurements of attenuation coefficient owing to the diffraction effect. In the existing correction method, we obtained the attenuation coefficient after correct the spectrum at each depth. However, this paper obtain the attenuation coefficient using lg-spectral difference approach and then correct errors. As a proposed method is not correction for the spectrum at each depth but the difference spectrum, we reduce the calculation. Also the correction is performed through the total frequency range, the accurate attenuation coefficient in whole bandwidth is produced.

• 대한치과의사협회지
• /
• 제51권6호
• /
• pp.322-329
• /
• 2013

Among the occlusal discrepancies, maxillary transverse deficiency is quite common in several reasons. The reasons are comprised of maxillary hypoplasia, thumb sucking habits, non-syndromic palatal synostosis and syndromal patients including cleft patients. Orthodontic treatment is used routinely to correct a deficiency in young patients while it has limitations for a skeletally mature patient. Surgical treatments help provide effective maxillary expansion to correct a deficiency in adults. Surgical methods can be categorized to segmental Le Fort I osteotomy and surgically assisted rapid maxillary expansion(SARME). Both methods seem successful but each method would have its own indication. We give a review on transverse maxillary deficiency and two surgical methods.

• 음성과학
• /
• 제7권2호
• /
• pp.7-18
• /
• 2000

The purpose of this study was to investigate the phonological error patterns of korean children with and without specific phonological disorders(SPD). In this study, 29 normally developing children and 10 SPD children were involved. The children were matched the percentage of consonants correct(PCC). 22 picture cards were used to elicit korean consonants in word initial syllable initial, word medial syllable initial, word medial syllable final, word final syllable final positions. The findings were as follows. First, the phonological error patterns of SPD were 1) similar to those of normal children with the same PCC, 2) similar to those of normal children with the lower PCC, or 3) unusual to those of normal children. Second,. korean children showed phonological processes reflecting the korean phonological characteristics: tensification, reduction of the word medial syllable final consonant. This study suggests that both the PCC and error patterns should be considered in assessing phonological abilities of children.

• 음성과학
• /
• 제10권2호
• /
• pp.15-25
• /
• 2003

In this paper, we propose an algorithm on OOV(Out-of-Vocabulary) rejection based on two-stage method. In the first stage, the algorithm rejects OOVs using generic word model, and then in the second stage, for further reduction of false acceptance, it rejects words which have low similarity to the candidate by measuring the distance between HMM models. For the experiment, we choose 20 in-vocabulary words out of PBW445 DB distributed by ETRI. In case that the first stage is processed only, the false acceptance is 3% with 100% correct acceptance, and in case both stages are processed, the false acceptance is reduced to 1% with 100% correct acceptance.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제54권10호
• /
• pp.581-586
• /
• 2005

The multi-beam side scan sonar system uses the towfish installed sonars, it is an equipment that search images of the bottom surface of the sea in real time. It is a typical equipment that is related to a sea investigation such as a geological survey, seabed communication cable and power line cable placing repair investigation, fish breeding ground investigation, sea purification, relic and mineral investigation, and mine and submarine search. Recently, it is used to sea purification and geological survey that require information of the correct surface of the seabed. Therefore, this research develops multi-beam sensors for a side scan sonar that supply various information with the fast scan speed and correct high resolution that is not a simple underwater investigation equipment.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권6호
• /
• pp.712-718
• /
• 1999

When a fault occurs in power transmission systems, protective relays play a roles of protecting the power system according to there setting values. Therefor, it is important that protective relays have high selectivity and sensitivity by correct setting the involves a large volume of data and is a complicated and very tedious, therefore vulnerable to the human errors. Also, it is very difficult to verify that the relays have correct operating parameters before the fault occurs. This paper porposed a method to testify the reliability of realys by showing the operation response to faults in the simulation of the real power system operation environment.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2002년도 ICCAS
• /
• pp.65.1-65
• /
• 2002

Recently, increased accessibility to the Internet makes it possible to access to Internet-connected devices easily. For this reason, anyone can reach and command any device that is connected to the network. But these teleoperation systems have several problems like the network time delay, data loss and development cost of an application for communication with each other. The network time delay phenomenon is the most important in teleoperation system, which disturbs a real time control. The loss data also causes some users not to send correct commands to device or not to receive correct information from devices. To develop an application to communicate between user and device, it needs a comp..

• 제어로봇시스템학회논문지
• /
• 제5권2호
• /
• pp.145-150
• /
• 1999

A real-time control system, composed of the controlled processor and the controller computer(s), may have a variety of task types, some of which have tight timing-constraints in generating the correct control input. The maximum period of those task failures tolerable by the system is called the hard deadline, which depends on not only fault characteristics but also task characteristics. In the paper, we extend a method deriving the hard deadline in LTI system executing single task. An algorithm to combine the deadlines of all the elementary tasks in the same operation-mode is proposed to derive the hard deadline of the entire system. For the end, we modify the state equation for the task to capture the effects of task failures (delays in producing correct values) and inter-correlation. We also classify the type of executing the tasks according to operation modes associated with relative importance of correlated levels among tasks, into series, parallel, and cascade modes. Some examples are presented to demonstrate the effectiveness of the proposed methods.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
• /
• pp.171-174
• /
• 2003

In this paper, we propose the method of stereo images composition using adaptive dense disparity estimation. For the correct composition of stereo image and 3D virtual object, we need correct marker position and depth information. The existing algorithms use position information of markers in stereo images for calculating depth of calibration object. But this depth information may be wrong in case of inaccurate marker tracking. Moreover in occlusion region, we can't know depth of 3D object, so we can't composite stereo images and 3D virtual object. In these reasons, the proposed algorithm uses adaptive dense disparity estimation for calculation of depth. The adaptive dense disparity estimation is the algorithm that use pixel-based disparity estimation and the search range is limited around calibration object.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
• /
• pp.353-356
• /
• 2000

In this paper, a high-performance and small-area floating-point divider, which is suitable for embedded processors and supports all rounding modes defined by IEEE 754 standard, is designed using the series expansion algorithm. This divider shares and fully utilizes the two MAC units for quadratical convergence to the correct quotient. The area increase of two MAC units due to the division is minimized in this design, so that it can be suitable for embedded processors. The tested HDL codes are synthesized and optimized with 0.35$\mu\textrm{m}$ CMOS standard celt libraries. The results show that the latency of the synthesized divider is 17.43 ㎱ in worst condition. But, the divider calculates the correct rounded quotient through only 6 cycles.