• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.10
• /
• pp.921-932
• /
• 2016

In this paper, a modified FSA(Frequency Scaling Algorithm) is proposed for KOMPSAT-5 high-resolution SAR image generation. In order to enhance performance of azimuth compression, degraded in sub-aperture processing due to the imperfect geometric parameter of data acquisition, the full-aperture signal processing algorithm is designed based on the exact time-frequency analysis. In addition, an azimuth scaling function is newly devised to make the full-aperture processing algorithm suitable for KOMPSAT-5 sliding-spotlight mode. Different from the previous sub-aperture FSA schemes, the suggested technique could accommodate the merit of unified signal processing structure regardless of operational modes of KOMPSAT-5. Through the point target simulation, it is verified that the suggested algorithm provides superior performance of azimuth compression over the existing full-aperture processing methods. The experimental results using real data acquired by KOMPSAT-5 are also given to demonstrate the effectiveness of our scheme as well.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2002.09a
• /
• pp.199-201
• /
• 2002

Cancer therapy using high-energy $^{12}$ C ions is successfully under way at HIMAC, Japan. An alternative beam to $^{12}$ C is $^{11}$ C ions. The merit of $^{11}$ C over $^{12}$ C is its capability for monitoring spatial distribution of the irradiated $^{11}$ C by observing the $\beta$$^{+}$ decay with a good position resolution. One of the several problems to be solved before its use for therapy is the amount of nuclear interaction that deteriorates the dose concentration owing to the Bragg curve. Utilizing the dedicated secondary beam course for R&D studies at HIMAC, we measured the total energy loss of $^{11}$ C ions in a scintillator block that simulates the soft tissue in human bodies. In addition to the total absorption $^{11}$ C peak, non-negligible bump-shaped contribution is observed in the energy spectrum. The origin of the bump contribution can be nuclear interaction of the incident $^{11}$ C ions with hydrogen and carbon atoms. Further studies to reduce the ambiguity in dose distribution are mentioned.

• 한국지구물리탐사학회:학술대회논문집
• /
• 1999.08a
• /
• pp.156-175
• /
• 1999

Recently the application of geophysical well logging to geotechnical site investigation is increasing, because the merit that geophysical logs provide the high resolution and in-situ physical properties in volumes of rock surrounding the borehole. Geophysical well logs are used to identify lithologic boundaries and fracture, to determine the physical properties of rock(i.e., density, velocity etc.), and to detect permeable fracture zones that could be conduits for ground water movement through the rocks. The principle of heat-pulse meter, the calibration of gamma-gamma logging, and principles and data processing of full waveform sonic logging are briefly reviewed, and the case studies of geophysical logs are discussed. Correlation between velocity by sonic logging and rock mass classification such as RMR(Rock Mass Rating) value is considered.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.556-560
• /
• 2005

The measurement method by Laser Speckle Interferometry which uses the interference law which will grow precedes and with it explains a resolution measurement ability and together the change of place arrowhead and general measurement, at real-time measurement sensitivity it has application boat song from candle precise measurement field it is increasing. But, currently the domestic application technique to sleeps and optical science military merit by optical science interferometer and directness it composes purchases to the level which it applies the expensive commercial business equipment the outside and in spite of the technical ripple effect is deficient even in many strong point. The hazard which complements like this problem point form technical development it leads from the research which it sees and an application degree and to sleep as the measurement equipment which tries to develop the small-sized optical science interference sensor and an interpretation program it raises it does.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.43 no.8 s.350
• /
• pp.19-26
• /
• 2006

In this paper, CMOS analog-to-digital converter (ADC) with a 6-bit 100MSPS at 1.8V is described. The architecture of the proposed ADC is based on a folding type ADC using resistive interpolation technique for low power consumption. Further, the number of folding blocks (NFB) is decreased by half of them compared to the conventional ones. A moebius-band averaging technique is adopted at the proposed ADC to improve performance. With the clock speed of 100MSPS, the ADC achieves an effective resolution bandwidth (ERBW) of 50MHz, while consuming only 4.5mW of power. The measured result of figure-of-merit (FoM) is 0.93pJ/convstep. The INL and DNL are within ${\pm}0.5 LSB$, respectively. The active chip occupies an area of $0.28mm^2$ in 0.18um CMOS technology.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1058-1061
• /
• 2004

Recently, According to companies of TFT LCD are making large sized products more and more. In the vortex of Products with a monitor and LCD TV is applied in a technique of a high viewing angle(FFS, IPS, VA). Also, as a high luminance, high speed response time, high degree of a color purity, and so on are continuing to develop a high performance, it is necessary to improve a specific character of high luminance that apply to LCD TV as a LCD BLU. Because a LCD panel for TV usually has a lower resolution that compare to a monitor, the structure of present backlight system can't put out its power even though it has a merit in transmission. Therefore, the examination of improvement about the high luminance direct typed BLU for LCD TV that presupposes several uses of CCFL(Cold Cathode Fluorescent Lamp) or EEFL(External Electrode Fluorescent Lamp)is actively being progressed. Although it is necessary to increase the number of lamps for applying high performance by the direct type, in this case, because we can design the character of luminance for adoption of high performance. We can satisfy with a level of luminance for LCD TV. Accordingly, we analyzed a change of the number of CCFL, mechanical and optical character to produce the direct typed backlight in 32inches spec. Consequently, we achieved luminance of 6597nit,which was including polarization film, and secured the standard for LCD TV.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.1
• /
• pp.33-40
• /
• 2007

RFID, a non-contact wireless identification technology is being noticed as a technology to alternate barcode system in distribution industry and general industry. Despite of merit of RFID, there are issues to be solved for practical use. One of them, which are most important, is resolution of user's information protection. RFID system without security function bears risk exposing personal data and user's privacy. In this paper, we propose mutual authentication protocol for RFID system in order to solve this security issue. This study aimed to protect user's privacy by providing dynamic ID for tag through authentication protocol safe from security threats. Information being transmitted between backend, reader and tag has no direct connection with ID of tag, and it conducts authentication process using one-way hash function, which prevents attacker's obtaining of tag information using information being transmitted.

• Journal of Yeungnam Medical Science
• /
• v.10 no.1
• /
• pp.127-134
• /
• 1993

Percutaneous needle biopsy of pulmonary lesion with use of fluoroscopic guidance is well established as a diagnostic tool but limited by the small size and inaccessibility of certain lesions. However, percutaneous needle biopsy has been used increasingly in relation to advance and the safty of smaller biopsy needle and new imaging modalities such as ultrasound and CT. CT, because of its characteristics of high resolution, allows tissue sampling with considerable safety from area that heretofore could not be visualized under fluoroscopy. The authors summarized 44 pulmonary lesions that underwent CT-guided transthoracic biopsy with fine-needle over a 14 month period and analyzed the sensitivity of PTNB. CT-guided PTNB was done with 20 gauge or 22 gauge Westcott biopoy needle(Manan medical products, USA). A diagnosis was made in 27 of 44 cases(61%) including malignany in 19 of 24 cases and benignancy in 8 of 20 cases. The pulmonary mass lesions were located at the peripheral zone of the lung field in 33 cases and at the central zone in 11 cases. Complications were observed in 2 cases which were pneumothorax and hemoptysis each but specific therapy was not required. The sensitivity of PTNB by one session was 61%(27/44). The sensitivity of malignancy was 79%(19/24) and benignancy was 40%(8/20). These results suggest the usefulness of PTNB using fine needles be increased in earlier diagnosis and improved staging of pulmonary nodular lesions without significant complications.

• Korea Journal of Hospital Management
• /
• v.5 no.1
• /
• pp.40-61
• /
• 2000

The purpose of this study is to promote the efficiency of the management of the controls organization in the university hospitals and general hospitals by evaluating the factors underlying organizational conflict. The subject population included 351 hospital workers randomly selected from two general hospitals of less than 200 beds and two university hospitals over 500 beds in Seoul area. Data were collected through a survey questionnaire. To define related factors for the level of conflict among departments in each hospitals multivariate regression analysis was conducted. Independent factors were characteristics of subjects, conflicting factors between the departments. The results are as follows: 1. Those in high job position group demonstrated significantly higher level of conflict between departments. Those working in the general hospitals, who were older and had long-term tenure at current working hospital had higher level of conflict between the departments. 2. Concerning the involvement of conflicting factors and the level of conflict in the employees' there was statistically significant positive correlation between reliability and job-related and intradepartmental level of conflict in university hospitals. There was a significant positive correlation between interdepartmental conflicting factors of mutual dependence, difference in goal/orientation and interdepartmental level of conflict. 3. In the university hospitals, among the interdepartmental factors, mutual dependence and difference in goal/orientation had statistically significant influence and showed a positive relationship with interdepartmental level of conflict. In the general hospitals, job position was a significant factor which showed that those in high position such as section chief or above, compared to those in general position had higher level of conflict. Among the interdepartmental characteristics, factors of mutual dependence and goal/orientation had statistically significant influence and showed a positive relationship with interdepartmental level of conflict. In the general hospitals setting efforts to reduce conflict in areas among workers with high position, old age, and long tenure and those in medical care department should be made and prudent management and planning for improved manpower and increased budget or efficient allocation and clear definition of job description are necessary to adequately assess. In the university hospitals setting efforts to reexaminitation of the organizational structure and efficiency conveyance of information and efforts to resolve conflict among young workers with lower level of education is need. This study has its own merit in comparing empirically the conflict among hospital workers in the university hospitals and general hospitals. Future study are needed with respect to the relationship between interdepartmental level of conflict and the effectiveness of the hospital organization for improved resolution of conflict in the organization and hospital management.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.16 no.6
• /
• pp.454-464
• /
• 2023

This paper proposes a low-power 8-bit asynchronous SAR ADC with a sampling rate of 1 MS/s for sensor node applications. The ADC uses bootstrapped switches to improve linearity and applies a VCM-based CDAC switching technique to reduce the power consumption and area of the DAC. Conventional synchronous SAR ADCs that operate in synchronization with an external clock suffer from high power consumption due to the use of a clock faster than the sampling rate, which can be overcome by using an asynchronous SAR ADC structure that handles internal comparisons in an asynchronous manner. In addition, the SAR logic is designed using dynamic logic circuits to reduce the large digital power consumption that occurs in low resolution ADC designs. The proposed ADC was simulated in a 180-nm CMOS process, and at a 1.8 V supply voltage and a sampling rate of 1 MS/s, it consumed 46.06 𝜇W of power, achieved an SNDR of 49.76 dB and an ENOB of 7.9738 bits, and obtained a FoM of 183.2 fJ/conv-step. The simulated DNL and INL are +0.186/-0.157 LSB and +0.111/-0.169 LSB.