부신 갈색세포종에서 생화학적 검사 및 MIBG Scan의 진단적 유용성

박형근,김정균,홍범식,김청수,박태한,안한종 大韓泌尿器科學會 1997 Korean Journal of Urology Vol.38 No.12

Rate Control Based Call Admission Control Scheme for CDMA2000 System

박형근,Park, Hyung-Kun The Korean Institute of Communications and Informa 2004 韓國通信學會論文誌 Vol.29 No.9B

In a COMA system, the capacity is variable and mainly depends on multiple access interference. The multiple access interference has a deep relationship with transmitted or received power. The capacity of COMA2000 system is considered to be limited by the forward link capacity. In this paper, we show that the forward link cell load can be represented by the total transmitted power of base station and we propose a forward link call admission control (CAC) strategy for COMA2000 system. The proposed call admission scheme adopts the rate control algorithm for data call. This call admission scheme enables the system to utilize radio resource dynamically by controlling data rate according to the cell load status, and enhance the system throughput and grade of service (GoS). quality of service(QoS) such as blocking and outage probability.

동적 환경 내에서의 자율 에이전트에 의한 다양한 행위의 설계 및 구현

박형근,박종희,Park, Hyung-Keun,Park, Jong-Hee 대한전자공학회 2001 電子工學會論文誌-CI (Computer and Information) Vol.38 No.3

에이전트의 정의와 구현에 관한 연구는 가상현실기술을 이용한 몰입형 교육 시스템 등의 구성에 있어서 매우 중요한 부분을 차지한다. 본 논문에서는 동적인 환경에서 에이전트의 행위의 효율적인 정의와 구현 방법을 제시하되 기존의 연구와 달리 행동의 다양성을 표현에 초점을 맞추고자 한다. 먼저 장이론에 기반하여 공간객체를 정의 한다. 장이론을 도입하여 공간객체를 정의함으로써 공간 객체에 대한 분류적 접근이 아닌 구조적인 접근이 가능해 지고, 공간객체의 동적인 생성 및 소멸과 전체적인 시공간 상황의 변화를 유도할 수 있게 된다, 다음으로 동적인 planning이 가능하도록 에이전트의 행위를 복합행위와 단위행동으로 구분한다, 마지막으로 에이전트와 관련된 객체의 관계에 따라 지식 베이스를 에이전트와 관련 객체들에 분산한다, 이를 통해 에이전트의 지식베이스의 효율적인 관리와 동적인 환경의 구축이 가능하다. 공간객체 내에서의 에이전트의 이동에 관한 상황을 구현함으로써 장이론에 기반한 공간객체의 정의와 행위의 복합행위와 단위행동으로의 구분, 그리고 에이전트와 관련 객체간의 지식 베이스의 분산의 효율성을 검증하였다. The design and implementation of agents is an essential part of the development of immersive types of tutoring systems using virtual reality. This paper proposes several effective mechanisms for the design and implementation of agents. Unlike existing researches we focus on accommodating diversity of agents' behavior in the proposed mechanisms. First, we define the space object based on the field theory. The introduction of the field theory allows us to approach the space objects in a structural manner rather than by their classification. We can also achieve dynamic genesis and extinction of the space objects, and derivation of overall changes in spatio-temporal situations. Second, we classify the behavior of agents into composite behaviors and primitive actions in order to achieve its dynamic planning. Finally, we distribute the knowledge among agents and their associated objects according to their interrelations. By this distribution, we can handle the otherwise prohibitively large amount of knowledge related to agents' behaviors and construct a dynamic environment. By implementing a situation with agent's navigation across a composite space object, we demonstrate the effectiveness of these schemes presented above.

MC-CDMA 시스템을 위한 채널 추정에 관한 연구

박형근,이윤호,김응배,차균현 한국통신학회 1999 韓國通信學會論文誌 Vol.24 No.8

Multi-carrier CDMA technique is more attractive in wireless communication system. It can support the effect of frequency diversity with higher spectral efficiency. In this paper, pilot symbol structure was proposed to estimate chann디 paramenters for MC-CDMA system and we analyzed the perfoemance of proposed MC-CDMA which compensates the received signals using the pilot symbols for link transmission. At first, we proposed the new method of pilot's usage for reverse link transmission that can distinguish accessing users whose signals undergo diggerent channels. And we analyzed the performance of coherent MC-CDMA reception using estimated channel parameters 최근 높은 주파수 효율과 주파수 다이버시티 효과의 제공을 가능케 하는 다중 반송파 CDMA (MC-CDMA) 기술은 무선통신에 있어서 점점 더 주목받게 되었다. 본 논문에서는 이러한 C-CDMA시스템에서의 채널 추정을 위한 파일럿 심볼 구조를 제안하고 그에 따른 신호의 보상을 통한 MC-CDMA시스템의 성능향상을 역 방향 링크에 대하여 분석하였다. 먼저 여러 다른 채널을 겪는 각 사용자들의 역 방향 신호에 대하여 파일럿 심볼을 이용한 새로운 채널 추정방법을 제안하고, 추정된 채널을 이용한 MC-CDMA 동기 복조기의 성능을 분석하였다.

기준 신호를 이용한 FM-CW 레이더의 VCO 비선형성 보정

박형근,김병욱,김영수 한국전자파학회 1999 한국전자파학회논문지 Vol.10 No.7

일반적으로 거리 탐지용 레이더로 FM-CW 레이더 방식을 사용한다. 이 경우 FM-CW의 신호원으로 사용 되는 전압제어발진기의 제어전압과 출력주파수의 비선형성이 측정결과에 영향을 주게 된다. 최근 비선형성 보정에 대한 신호처리와 하드웨어적인 방법으로 많은 연구가 진행되고 있다. 본 논문에서는 기준 선호를 이 용하여 전압제어발진기의 비선형성으로 인해 측정결과에 발생하는 거리 단면의 왜곡을 보정하는 신호처리 기 법을 제안하였다. 이에 대한 성능을 검증하기 위해서 간단한 실험을 수행하였고, 결과를 제시하였다. 제안한 기법에 의해 거리 단면 왜곡의 영향 감소와 분해능이 향상됨을 확인할 수 있었다. When a FM-CW radar is used to measure the target distance, the nonlinearity relationship between the VCO control voltage and the output frequency makes an adverse effect on the measurement accuracy. Recently, many nonlinearity correction schemes using signal processing techniques and dedicated hardwares have been studied. This paper presents a signal processing technique to compensate for the VCO nonlinearity using a reference signal. To demonstrate the validity of the presented technique, several experiments were conducted and the results show reduction of the distortion in the range profile and the resolution improvement.

반도체 제조공정의 포토레지스트 정량 토출 펌프에 관한 연구

박형근 한국산학기술학회 2022 한국산학기술학회논문지 Vol.23 No.9

This study developed a pump capable of emitting an expensive photoresist used in TRACK equipment of semiconductor photoresist material manufacturing on a wafer quantitatively and at constant pressure. Technically, the photoresist emission is required to be highly reliable without allowing a single error, even under the mass production of the semiconductor. In addition, semiconductor manufacturing lines continue to make efforts to reduce manufacturing costs and currently use a low photoresist volume of 0.8cc to 1.5cc to coat it on a 12-inch wafer. So, as the photoresist volume usage continues to decrease, the precision and accuracy of the quantitative emission and the cut-off/suck-back control are essential measures to improve the semiconductor yield. Along these lines, the pump developed in this study consisted of a cut-off/suck-back valve drive with an ultra-small diaphragm and a linear motor to achieve high semiconductor yield. In particular, for 5ml of the photoresist discharge, the ± 0.02ml of the existing Millipore Intelligent RDS pump showed the best quantitative photoresist emission characteristics within ±0.008ml and up to ±0.018ml. 본 논문에서는 반도체 제조공정의 포토공정에 사용되는 TRACK 설비에서 고가의 포토레지스트를 웨이퍼에 정량 및 정압으로 토출할 수 있는 펌프를 제안하였다. 포토레지스트의 기술적 요구사항은 대량생산의 특성상 단한번의 오류도 허용되지 않는 높은 수준의 신뢰성을 요구하고 있다. 또한, 반도체 제조라인에서는 원가절감을 위해 지속적인 노력을 기울여 현재 12인치 웨이퍼 코팅을 기준으로 0.8cc~1.5cc의 포토레지스트를 사용하고 있다. 포토레지스트 사용량이 줄어들면서 정량토출 및 Cut-off/suck-back 제어의 정밀도와 정확성 향상이 수율 향상을 위한 대책으로 필수적이다. 제안된 펌프는 초소형 다이아프램과 리니어 모터를 이용한 Cut-off/Suck-back valve 구동장치로 구성되며, 5ml 토출을 기준으로 기존 Millipore사 Intelligen RDS 펌프의 ±0.02ml 이내 대비 최소 ±0.008ml 이내에서 최대 ±0.018ml 이내의 정량 특성을 나타내어 각 구간 측정 오차가 ±0.02ml 범위내에 포함됨을 확인하였다.

퍼지 확률 기울기 알고리즘을 이용한 등화기 설계

박형근,나유찬,Park, Hyoung-Keun,Ra, Yoo-Chan 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.1

본 논문에서는 스텝 크기(step size)를 자동적으로 조절함으로써 빠른 수렴비와 낮은 초과 MSE를 갖는 TS(Tagaki-Sugeno) 퍼지 모델과 ISI에 강하고 위상변화에 둔감한 CMA(constant modulus algorithm)를 접목시킨 새로운 퍼지 확률 기울기(Fuzzy Stochastic Gradient) 알고리즘을 제시하고 비이상적인 전송채널에 의해서 발생한 왜곡을 보상함으로써 수신 측에서 비트 검출 오류를 감소시키기 위하여 국내 지상파 디지털 TV의 표준으로 되어 있는 VSB 방식에 적용 가능한 등화기(equalizer)를 구현하였다. For high-speed data communication in band-limited channels, main of the bit error are fading and ISI(Inter-Symbol Interference). The common way of dealing with ISI is using equalization in the receiver. In this thesis, channel adaptive equalizer which uses Fuzzy Stochastic Gradient(FSG) and Constant Modulus Algorithm(CMA) is nonlinear equalizer, or Blind equalizer, that works directly on the signals with no training sequences required. This equalizer employs Takagi-Sugeno's fuzzy model that uses the FSG algorithm, to automatically regulate the step size of the descent gradient vector, combining fast convergence rate and low mean square error(MSE), and the CMA which is a special case of Godard's algorithm, to having multiple dispersion constants($R_p$).

혈청 전립선특이항원 수치만 증가한 환자에서 12부위 확장생검법의 유용성

박형근,변석수,손동완,홍성규,이은식,이상은,이학종 대한비뇨의학회 2005 Investigative and Clinical Urology Vol.46 No.5

Purpose: We evaluated the improvement in the rate of prostate cancer detection with the use of an extensive 12-site biopsy protocol in patients with only an elevated level of serum prostate-specific antigen(PSA). Materials and Methods: A total of 109 men with elevated PSA levels between 3 and 20ng/ml, but with no abnormal finding on digital rectal and transrectal ultrasound examinations, received transrectal ultrasound- guided prostate biopsies, which were performed at 12 sites, including the routine sextant and 6 far lateral regions(lateral apex, mid-lobe and base). The improvement in the detection rate was assessed according to the PSA level and prostate volume. Results: The mean age and PSA level of the patients were 63.5±8.6 years and 7.0±3.7ng/ml, respectively. Twenty-eight(25.7%) out of 109 men were diagnosed with prostate cancer. A traditional sextant biopsy detected 19(67.9%) of the 28 prostate cancer patients, while 9(32.1%) cancers were detected in the lateral region only. Overall, this extensive protocol resulted in a significant improvement, 8.3%(17.4 to 25.7%), in the detection rate (p=0.032). The improvement in men with a PSA of 10ng/ml or less was 8.1%(14.0% to 22.1%, p=0.007) and in those with a PSA greater than 10 ng/ml the improvement was 8.7%(30.4% to 39.1%, p=0.162). The improvement in men with a prostate volume of 50cc or less was 8.0%(22.3% to 30.3%, p=0.083) and in those with a prostate volume greater than 50cc this was 9.1%(6.1% to 15.2%, p=0.043). Conclusions: The twelve-site biopsy protocol is a more efficient method in men with a PSA and prostate volume of 10ng/ml or less and greater than 50cc, respectively, compared to the sextant protocol.

16 Multidetector Spiral CT (MDCT)를 이용한 신장의 관상영상의 임상적 유용성: 기존 축상영상과의 비교

박형근,정창욱,변석수,이학종,황성일,김승협,이상은 대한비뇨의학회 2005 Investigative and Clinical Urology Vol.46 No.5

Purpose: We evaluated the clinical usefulness of coronal reformatted renal images from raw 16 Multidetector Spiral CT(MDCT) data in the evaluation of the renal vascular anatomy and renal lesions. Materials and Methods: Twenty-one patients, who had undergone a nephrectomy, were studied, including 16 with renal cell carcinomas, 3 with transitional cell carcinomas and 2 with renal injuries due to renal trauma or a huge cyst rupture. The 5mm thickness summated axial and reformatted coronal renal CT images were retrospectively evaluated by two reviewers. Self-administered visual analogue scales were used to assess the subjective perception score in evaluating the renal vascular anatomy and anatomical perception of the renal lesions on the axial and coronal images, or both, respectively. The numbers of axial and coronal CT image cuts needed to evaluate the renal vascular anatomy and renal lesions were also counted. Results: Although one reviewer showed no statistical difference in preference toward the axial and coronal images, or both(ANOVA, p=0.36), the other reviewer preferred the coronal or combined images to that of the axial images in evaluating the vascular anatomy(ANOVA, p<0.05). Less image cuts were needed in evaluating the renal vascular anatomy in the coronal compared to the axial images(Student’s t-test(paired), p<0.01). Both the reviewers preferred the coronal or combined images in the anatomical perception of renal lesions(ANOVA, p<0.01). Also, in the perception of renal lesions, the coronal images needed less image cuts than the axial images(Student’s t-test(paired), p<0.01). Conclusions: Coronal reformatted renal images from raw MDCT data allow for the rapid and easy interpretation of the renal vascular anatomy and renal lesions.

2개 이상의 다른 Gleason score를 보인 전립선 생검에서 근치적 전립선적출술 후 Gleason score의 일치도 평가

박형근,이상욱,변석수,이상은,이은식 대한비뇨의학회 2005 Investigative and Clinical Urology Vol.46 No.5

Purpose: We evaluated the variables that may predict the final Gleason score of a radical prostatectomy in the patients showing more than two different Gleason scores in their positive core biopsy specimens. Materials and Methods: We reviewed the pathological data of patients diagnosed with prostate cancer using extended(12 site or more) needle biopsies who underwent a radical retropubic prostatectomy. A total of 73 patients showed more than two different Gleason scores in their biopsy specimen. The following parameters were assessed: highest Gleason score in the biopsy specimen, the Gleason score of the highest tumor percentage in the core and the highest tumor ratio score(Gleason score of highest total tumor length of same Gleason score/total core length of same Gleason score). Concordance of the Gleason scores between the biopsy specimen and prostatectomy was also examined. Results: The highest tumor ratio score showed the highest(64.4%) concordance rate. The concordance rates of the Gleason scores of the highest tumor percentage in the core and the largest linear cancer length were 59 and 58%, respectively. The concordance rate of the highest Gleason score in the biopsy specimens was only 47%. When stratified by grade: well differentiated(Gleason score=6), moderate(7) and poorly differentiated(8-10), the grade concordance rate of the highest tumor ratio score was 73%. The grade concordance rates of the highest and largest linear cancer length Gleason scores were 64.4 and 64.3%, respectively. Conclusions: If a biopsy specimen shows more than two different Gleason scores in positive cores, the highest tumor ratio score may be the most useful variable for predicting the final Gleason score from radical prostatectomy specimens.