• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.3
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• pp.259-268
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• 2014

Non-invasive technologies in skin research have enabled to use a live image of living skin without a biopsy or histologic processing of tissue. Confocal scanning laser microscope (CSLM) operated at a near-infrared wavelength of 830 nm allows visualization of inner structure of skin as a non-invasive manner. According to previous researches using CSLM, melanin cap and papillary ring were clearly observed in pigmented areas between stratum basale and papillary dermis. In this study, conversional analysis of CSLM digital images into numerical estimation using scanning probe image processor (SPIP) software was attempted for the first time. It is concluded that a quantification of CSLM images can pave way to expand the field of applications of CSLM.

• Journal of the Korea Society of Computer and Information
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• v.19 no.2
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• pp.39-48
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• 2014

In this paper, we propose an efficient dynamic workload balancing strategy which improves the performance of high-performance computing system. The key idea of this dynamic workload balancing strategy is to minimize execution time of each job and to maximize the system throughput by effectively using system resource such as CPU, memory. Also, this strategy dynamically allocates job by considering demanded memory size of executing job and workload status of each node. If an overload node occurs due to allocated job, the proposed scheme migrates job, executing in overload nodes, to another free nodes and reduces the waiting time and execution time of job by balancing workload of each node. Through simulation, we show that the proposed dynamic workload balancing strategy based on CPU, memory improves the performance of high-performance computing system compared to previous strategies.

• Journal of the Korea Convergence Society
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• v.8 no.9
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• pp.9-16
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• 2017

In this paper, sub-microwave oscillator sensor is proposed to non-invasively monitor the glucose concentration level of the human biological tissue by oscillation frequency variation. Inductive slot in the ground plane of the microstrip line is combined with the biological tissue, to realize the resonator as a part of the oscillator sensor. The phantom box mimicking the human tissue is introduced for simulation of the resonator which resonance frequency correspondingly shifts up on three step glucose concentration levels(0, 400, 800 mg/dL). Oscillator sensor circuit is fabricated as a prototype. Pig tissues instead of human is used. Oscillation frequency shift of about 14 MHz per glucose level of 400 mg/dL has been successfully measured around 1,100 MHz. This proves that the proposed sensor is applicable to a blood glucose sensor.

• Journal of Chest Surgery
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• v.40 no.12
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• pp.825-830
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• 2007

Background: Minimally invasive cardiac surgery appears to offer certain advantages such as earlier postoperative recovery and a greater cosmetic effect than that achieved through conventional sternotomy. However, this approach has not yet been widely adopted in Korea to replace complex open heart surgery such as mitral valve reconstruction. This study compared the results of robot assisted minimally invasive mitral valve repair with those results of conventional sternotomy. Material and Method: From December 1993 to December 2005, 520 consecutive patients underwent mitral valve reconstruction for mitral regurgitation in our institution. These patients were subdivided according to those whose surgery used the conventional sternotomy approach (Group S, n=432) and those who underwent minimally invasive right anterior thoracotomy (Group M, n=88); we then compared the clinical results of both groups. When we performed minimally invasive right thoracotomy, we used a robot (AESOP 3000) and made an incision less than 5 cm. Result: Our study patients in both groups were similar for their age, gender and preoperative ejection fraction. There were two hospital mortalities in group S. but there was no mortality in the group M patients. Significant reductions in the ICU stay and the postoperative hospital stay were observed in the group M patients compared with the group S patients. However, both the bypass time and the aortic cross-clamp time were significantly longer in the group M patients. In spite of the confined incision in the group M patients, there were no limitations on the mitral valve repair techniques. There was a similar frequency of postoperative significant residual mitral regurgitation in both groups. Conclusion: In this study, the minimally invasive mitral valve repair showed comparable early results with the conventional sternotomy patients. We will now need long-term follow-up of these patients who underwent minimally invasive mitral valve repair, but we anticipate that based on the results of this study, we will begin to routinely perform minimally invasive cardiac surgery as out primary approach for mitral valve reconstruction.

• Journal of Chest Surgery
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• v.31 no.10
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• pp.973-981
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• 1998

Background: About 30% to 40% of the patients with pathologic stage I non-small cell lung cancer (NSCLC) die within 5 years after complete resection. The identification of poor prognostic factors and the application of additional treatment are very important to improve the survival rate in resected stage I NSCLC. Materials and methods: Sixty-eight(68) patients who had been diagnosed postoperatively between Janury 1989 and December 1995 as having stage I non-small cell lung cancer according to the TNM classification were studied. The postoperative 5-year survival rate was calculated with the Kaplan-Meier method, and clinico- histopathologic factors including age, sex, operative method, type of tumor cell, T factor, grade of the differentiation in a squamous cell carcinoma, invasion of blood vessel and expression of the nm23-H1 protein were investigated and analyzed. Results: The median survival of the entire group of patients was 58$\pm$3 months, with a 5-year survival of 58.9%. In univariate analysis, invasion of blood vessel and poor differentiation of the tumor cell in a squamous cell carcinoma significantly worsened the survival. In multivariate analysis, invasion of blood vessel and grade of the differentiation of the tumor cells in a squamous cell carcinoma remained independent prognostic factors. High expression of the nm23-H1 protein was related to a high postoperative 5-year survival in comparision with low expression of the nm23-H1 pretein (73.0% vs 50.7%), but there was no statistical significance. Conclusions: These results highlight the negative prognostic value of poor differentiation of tumor cells in a squamous cell carcinoma and invasion of blood vessel in stage I non-small cell lung cancer. Also, further studies are necessary to be determined prognostic value of the T factor and expression of the nm23 protein in non-small cell lung cancer.

• Journal of Chest Surgery
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• v.31 no.1
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• pp.52-54
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• 1998

Recently, several versatile approaches via limited incision have been developed for minimally invasive cardiac surgery. As the incision is limited, it is often dfficult to get a satisfactory operative field, especially for the manipulation of two separate lesions such as simultaneous mitral and aortic valve disease with a single limited incision. Here, we describe a case of successful double valve replacement via ministernotomy, which was followed by two cases of minimally invasive aortic valve replacement via transsternal approach. The operative field was unexceptionally satisfactory and the postoperative patient's acceptance was high. The methodology is described with a review of the relevant literatures.

• Journal of IKEEE
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• v.11 no.4
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• pp.293-296
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• 2007

A novel sensitive and non-invasive ring-type glucose probe was designed and measured. The magnitude and phase of return loss change with different concentration of the glucose solution inside the loop structure. Ring type probe is more advantageous than open ended probe to measure electrical characteristics under the skin. The maximum difference of return loss was 0.94 for the concentration difference of 0% and 20% at 285MHz and more sensitive in low frequency.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.499-505
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• 1997

A non-invasive technique to measure absorption and scattering coefficients was investigated The reflected backscattered light from the surface of phantom and biological tissue was obtained by using a time-correlated single photon counting system in pico-second time domain. The absorption and scattering coefficients were acquired by the time of peak and asymptotic behavior of the time-resolved reflectance curve and agreed well the ones that is obtained with deconvolution method It was found that the approximation method was good for biological medium to calculate optical properties due to its convenience and accuracy.

• Journal of Chest Surgery
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• v.39 no.3 s.260
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• pp.255-259
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• 2006

The operation for esophageal cancer is both complex and challenging, and may be associated with significant morbidity and mortality compared to other oncologic surgeries. Minimally invasive surgeries have been applied on various kinds of surgery to enhance better recovery with minimal surgical complications. But for the esophageal cancer, it has not been actively applied yet. With improvement in instrumentations and increasing experience with endoscopic surgical techniques, minimally invasive surgical approaches to esophageal cancer are being explored to determine feasibility, results and potential advantages. We experienced eight cases of minimally invasive surgery for esophageal cancer and report here focusing on surgical techniques and tips.

• Korean Journal of Head & Neck Oncology
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• v.16 no.2
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• pp.177-181
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• 2000

배경 및 목적: Theodor Kocker에 의해 일반화된 전통적인 갑상선 수술방법은 갑상선 질환의 종류 및 정도, 수술범위와 상관없이 광범위한 수술범위로 인한 조직 손상으로 인해 수술후 환자들의 여러가지 불편감은 물론 경부의 넓은 부위의 통증과 경부 피부부종, 장액종, 혈종 등과 같은 후유증을 동반할 수 있다. 최근 본 저자들은 이같은 전통적 갑상선 수술의 부작용을 최소화하기 위해 작은 피부절개($3{\sim}4.5cm$) 후 피하 피판(subplatysmal skin flap) 없이 직접 갑상선으로 접근하는 새로운 수술기법으로서 최소침습 갑상선 수술기법을 개발하였기에 그 술식을 소개하고 전통적인 갑상선 절제술에 대한 우월성을 확인하고자 본 연구를 시행하였다. 대상 및 방법: 1999년 1월 15일 부터 2000년 1월 14일까지 573예의 갑상선 수술 예 중 최소침습 갑상선절제술이 시행되었던 466예와 1998년 1월 15일부터 1999년 1월 14일까지 전통적 갑상선 수술을 시행한 549예 중 거대 종양(양성>6cm, 악성>5cm), 흉골하 선종, 국소진행암, 재발암, 측경부의 다발성 림프절 전이가 있었던 112예를 제외한 437예의 임상병리적 특성과 피부절개 길이, 수술 시간, 수술중 출혈양, 수술후 진통제 요구빈도 및 재윈기간, 수술 후 합병증 발생빈도를 비교 분석하였다. 결 과: 두 군간의 임상병리적 특성상의 유의한 차이는 없었다. 피부절개 길이($3.7{\pm}0.7cm,\;vs\;9.6{\pm}3.3cm$), 수술 시간($57.6{\pm}11.7$분 vs $85.2{\pm}32.3$분) 수술 중 출혈양($18.4{\pm}15.3ml\;vs\;43.1{\pm}21.8ml$), 수술후 재원기간($1.6{\pm}0.5$일 vs $4.3{\pm}1.6$일), 및 수술후 진통제 요구빈도가 전통적 수술군에 비해 최소침습 수술군에서 통계적으로 유의하게 감소되었으나(p<0.05), 수술후 장액종 및 혈종 형성, 일시적인 음색변화, 일시적인 저칼슘혈증과 같은 합병증의 발생빈도는 각각 4.3%(n=20)와 4.8%(n=21)로 두 군간에 유의한 차이가 없었다. 결 론: 최소침습 갑상선 수술법은 새로운 수술기구의 도입 없이도 갑상선 수술의 충분한 시야를 확보할 수 있고 안전하고 간단하게 시행할 수 있으며, 기존 수술법으로 인한 부작용을 최소화할 수 있어 전통적 인 수술법을 대치할 수 있는 새로운 방법으로 사료된다.