해석력 관점의 의사결정나무 안정성 분석 – 대표적인 알고리즘을 중심으로

이정언,홍정식 한국경영과학회 2022 한국경영과학회 학술대회논문집 Vol.2022 No.6

석탄연소 보일러에서 생성된 석탄회의 분석과 형성 메커니즘 해석에 대한 연구

이정언,이재근,Lee, Jung Eun,Lee, Jae Keun 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.12

Fly ash produced in coal combustion is a fine-grained material consisting mostly of spherical, glassy, and porous particles. A study on the formation mechanism of the fly ash from coal particles in the pulverized coal power plant is investigated with a physical, morphological, and chemical characteristic analysis of fly ash collected from the Samchonpo power plant. This study may contribute to the data base of domestic fly ash, the improvement of combustion efficiency, fouling phenomena and ash collection in the electrostatic precipitator. The physical property of fly ash is determined using a particle counter for the measurement of ash size distribution. Morphological characteristic of fly ash is performed using a scanning electron micrograph. The chemical components of fly ash are determined using an inductively coupled plasma emission spectrometry(ICP). The distribution of fly ash size was bi-modal and ranged from 12 to $19{\mu}m$ in mass median diameter. Exposure conditions of flue gas temperature and duration within the combustion zone of the boiler played an important role on the morphological properties of the fly ash such as shape, particle size and chemical components. The evolution of ash formation during pulverized coal combustion has revealed three major mechanisms by large particle formation due to break-up process, gas to particle conversion and growth by coagulation and agglomeration.

Attribute von Human Ressourcen, HR-Bündelung und Unternehmenserfolg: Ressourcen-orientierte Perspektive

이정언,김강식 한독경상학회 2011 經商論叢 Vol.29 No.2

Die Diskussion über den Beitrag der Humanressourcen (HR) zum Unternehmenserfolg ist in den ressourcenorientierten Theorien und der strategischen Perspektive des Human Resource Management (HRM) entwickelt worden. Die bisherigen Studien haben aufgezeigt, dass ein effizienter Einsatz von HR und HR-Maßnahmen einen wesentlichen Beitrag zur Erzielung des Unternehmenserfolgs leistet. Während die bisherigen Studien die Notwendigkeit der HR zum Unternehmenserfolg aufgewiesen haben, gilt es weiterhin, sich mit der Frage auseinanderzusetzen, wie HR und HR-Maßnahmen einen Beitrag zu der Nachhaltigkeit des Unternehmenserfolgs leisten können. Das Ziel der vorliegenden Untersuchung ist es, hierzu Erkenntnisse zu gewinnen. Zu diesem Zweck wird die Untersuchung mittels Analyse der Fallstudien in vier High Performance Unternehmen explorativ durchgeführt. Die Ergebnisse zeigen, dass hoch qualifizierte HR ein wesentlicher Faktor zur Erzielung des nachhaltigen Unternehmenserfolgs sind, wobei interne Imitierbarkeit und Substituierbarkeit eine wesentliche Rolle spielen. Die Analyse verdeutlicht, dass ein leistungs-bzw. fähigkeitsorientiertes HRM-System zum nachhaltigen Unternehmenserfolg beiträgt. Allerdings wird festgestellt, dass HRM-Systeme und -Praktiken den nachhaltigen Unternehmenserfolg indirekt fördern. In dieser Hinsicht leistet die vorliegende Untersuchung einen wesentlichen Beitrag dazu, existierende Theorien des HRM zu modifizieren, zu verfeinern und zu konkretisieren.

미세입자(微細粒子)를 함유(含有)한 슬러지의 고효율(高效率) 탈수(脫水) 연구

이정언,이재근,Lee, Jung-Eun,Lee, Jae-Keun 한국자원리싸이클링학회 2006 資源 리싸이클링 Vol.15 No.4

입자의 크기가 $5{\mu}m$ 이하인 미세입자를 함유한 안료 슬러지를 탈수하여 케이크화될 때 기공의 크기가 매우 작아 물의 배출이 어려운 특성이 있다. 기존의 외부가압력으로 탈수하는 기계식 탈수방법으로 탈수하기는 어렵다. 본 연구는 케이크 층에 저온 열을 인가하여 케이크 충의 기공으로부터 물을 원활하게 배출하여 탈수율을 향상시키고자 하는 연구이다. 케이크 층에 일정한 온도를 공급 할 수 있는 Piston형 열 탈수장치를 구축하여 미세 안료 입자 200g에 대하여 탈수 실험을 수행한 결과 여액량은 176.8g, 케이크 무게는 19.4g, 케이크 두께는 4.2mm로 측정되었으며, 함수율은 47wt%이며 면적당 건조 입자의 잔류량(여과 속도)은 $2.1DS\;m^{2}{\cdot}cycle$로 분석되었다. 이 결과는 기존의 기계식 탈수 방법에 의한 결과에 비하여 여액량은 증가하였으며, 케이크 무게와 두께는 감소하였고 탈수속도는 증가하였다. 그리고 함수율은 약 30%감소하여, 전반적으로 탈수율이 매우 향상되는 결과를 도출하였다. 그 이유는 케이크 층에 열을 인가함으로서 케이크 기공에 작용하는 내부 증발압으로 인해 물이 케이크 충으로부터 원활하게 배출되었기 때문이다. 따라서 본 연구는 미세 입자를 함유한 슬러지의 감량화를 위한 고효율 탈수 시스템 구축에 있어 매우 유용한 기술로 평가된다. There was some difficulty dewatering properties due to small porosity diameter of cake, when pigment sludge contained fine particle was formed by cake under the dewatering. It was difficult to dewater the sludge with fine particles with the conventional mechanical dewatering method. This study was to improve the dewatering rate as discharging the water from porosity of cake easily, supplying the low heat to the cake layer. Thermal dewatering equipment of piston type to keep up constant temperature on the cake was set up and relative experiment was conducted for sludge of 200 g with fine pigment particle. As test results. filtration of 176.8 g, cake weight of 19.4 g, cake thickness of 4.2 mm was measured, and it was analyzed that the water content of cake was 47 wt% and dewatering velocity, which moaned the residual d교 sloid amount per dewatering area, was $2.1DS\;m^{2}{\cdot}cycle$. This results showed that filtration increased, cake weight and thickness decreased and dewatering velocity increased against mechanical dewatering method. And water content of cake decreased about 30%, so the result which dewatering rate improved was drew generally. The reason is that the inner vapor pressure working at the cake porosity increased as applying the low heat to the cake layer, which lead to discharge the water from porosity easily. Therefore, this study was estimated by the useful technology for sludge reduction.

셀룰로오스 나노피브릴 함유 PVA 고배향 나노섬유의 제조

이정언,임종철,김미경,김기영,염정현 한국고분자학회 2023 한국고분자학회 학술대회 연구논문 초록집 Vol.48 No.1

석탄회 첨가에 따른 하수슬러지의 탈수율 향상에 관한 연구

이정언 대한환경공학회 2003 대한환경공학회 학술발표논문집 Vol.2003 No.12

폴리에틸렌 기반 통기성 보온필름의 제조

이정언,정재훈,김태영,김영권,한명동,염정현 한국고분자학회 2023 한국고분자학회 학술대회 연구논문 초록집 Vol.48 No.1

정수 슬러지에 대한 필터프레스의 탈수 특성

이정언 대한환경공학회 2002 대한환경공학회 학술발표논문집 Vol.2002 No.12

Characteristics of Invasive Micropapillary Carcinoma of the Breast: In Comparison with Invasive Ductal Carcinoma

이정언,김성훈,허성모,이세경,김완욱,김상민,조준호,김정한,김지수,남석진,양정현 한국유방암학회 2010 Journal of breast cancer Vol.13 No.2

Purpose: Invasive micropapillary carcinoma (IMPC) of the breast is a rare and associated with high incidence of lymph node metastasis and poor outcome. The aims of this study were to provide a comprehensive analysis of clinicopathologic and immunohistochemical characteristics of IMPC and to elucidate the differences between IMPC and invasive ductal carcinoma (IDC). Methods: Sixty-one patients of IMPC were identified by retrospective review of database from January 2004 to December 2008. 221 patients were randomly selected among the IDC patients who received operation during the same period. Two groups were compared with uni- and multivariate analysis. Results: We observed significant differences in mean number of metastatic lymph nodes (6.1 vs. 1.9, p=0.001), positivity of lymph node (70.5% vs. 45.2%, p<0.001), and presence of lymphatic vessel invasion (75.4% vs. 34.8%,p<0.001) between IMPC and IDC patients. Although it has been known that triple negative breast cancer (TNBC) have lymphotropic tendency in their early T stage, 11.8% (26/221) of IDC and 3.3% (2/61) of IMPC patients were TNBC in this study (p=0.050). In multivariate analysis, IMPC histology showed no correlation with disease-free survival (DFS) and the lymphatic vessel invasion was a significant predictor of DFS. Conclusion: The results of this study confirm that IMPC is unique subtype of breast cancer that is commonly accompanied by axillary lymph node metastasis and shows poor outcome, although it rarely presents the pattern of TNBC. Lymphatic vessel invasion rather than histology of IMPC seems to be more closely related to DFS.

BRCA2 돌연변이 보인자의 양측성 예방적 유방절제술에서 우연히 발견된 유관 상피내암 1예

이정언,최민영,김성원,이세경,허성모,김상민,구민영,배수연,최준호,김정한,김지수,남석진,양정현 한국유방암학회 2010 Journal of breast cancer Vol.13 No.3

In women at high-risk for breast cancer with a BRCA mutation, bilateral prophylactic mastectomy (BPM) may achieve a risk reduction. A 35-year-old woman had a strong family history of breast and ovarian cancer. She had a regular checkup and found masses in both breasts that confirmed intraductal papillomas and atypical ductal hyperplasia after vacuum assisted mass excision. When she was referred to our clinic, the genetic testing for BRCA mutation was recommended to her sister that managed for ovarian cancer. It was resulted in the positive for the BRCA2 mutation, so she had checked the genetic testing which resulted in the same as the mutation. After sufficient counseling, she decided to undergo BPM and immediate reconstruction. She is satisfied with the result of surgery. This is the first report of BPM of asymptomatic BRCA2 mutation carrier in Korea and BPM should be considered as a risk-reducing option for BRCA mutation carriers.