수조실험을 통한 해저지반 굴삭용 워터젯 장비의 성능평가에 관한 연구

나경원(Kyoung-Won Na),조효제(Hyo-Jae Jo),백동일(Dong-Il Baek),황재혁(Jae-Hyuk Hwang),한성훈(Sung-Hoon Han),장민석(Min-Suk Jang),김재희(Jae-Heui Kim) 한국해양공학회 2015 韓國海洋工學會誌 Vol.29 No.6

The demand for subsea cables and pipelines that transfer marine energy resources onshore has recently increased. Laying these underground after trenching is one engineering method to stabilize exposed subsea cables and pipelines. This experimental study found the optimum conditions for operating two types of waterjet arms mounted on an ROV trencher. A waterjet arm for trenching the seabed was scaled down at a ratio of 1:6, and a comparative analysis was conducted using diverse parameters. The results of this research provide a practical fundamental database to assist in making decisions about the ROV trencher performance in advance.

부유식 해상태양광 발전을 위한 단위 플랫폼 구조물의 실해역 성능평가

나경원(Kyoung Won Na),추진훈(JinHun Choo),이병준(Byung Jun Lee) 한국신재생에너지학회 2021 신재생에너지 Vol.17 No.3

Recently, the Korean government announced a plan to activate renewable energies, with focus on clean energy sources such as solar and wind power as the core and the goal of achieving carbon neutrality by 2050. Unlike other photovoltaic (PV) systems, offshore PV installations are advantageous for large-scale expansion because of the ease of securing sites; they also enable lowering the power generation costs based on construction of large-scale power facilities of megawatt class or higher owing to low noise and landscape damage. However, any power generation should proceed with consideration of the special environmental conditions of the ocean. Above all, when installing large-scale facilities, it is important to reduce fluctuations of the structure and secure stability to actively respond to waves. This study is concerned with the development of a floating body technology that actively responds to waves so as to enable commercialization of offshore solar power. A unit platform for research and development on offshore PV generation was installed in the Saemangeum sea, and the structural fluctuations and stability were analyzed to ensure conformity with the major performance indicators.

셰일가스 개발 시 적용되는 수압파쇄공법에 의한 환경문제

한협조,김경웅,나경원,박희원,이진수,심연식,Han, Hyeop-Jo,Kim, Kyoung-Woong,Na, Kyung-Won,Park, Hee-Won,Lee, Jin-Soo,Shim, Yon-Sik 대한자원환경지질학회 2013 자원환경지질 Vol.46 No.1

본 연구에서는 최근 전 세계적으로 이슈가 되고 있는 셰일가스 개발 과정 중 발생 가능한 환경문제에 대해 고찰하고자 하였다. 셰일가스는 개발 가능한 자원량 측면에서 매우 우수하며, 기존의 석유 및 석탄에 비해 이산화탄소 및 아황산가스 배출량도 적은 친환경적인 연료이다. 셰일가스가 부존하는 지층의 특성상 개발 과정 중 유체투과도를 높이는 수압파쇄공법 적용이 필수적이나, 이러한 기술 적용에 따라 수질, 토양, 대기 오염 등 다양한 환경문제의 발생이 예상된다. 셰일가스 개발에 따른 오염은 지상 및 함수층 주변에서 발생 가능하며, 따라서 셰일가스 개발은 환경적으로 위험 요소가 될 수 있다. 그러므로 셰일가스 개발 시 발생 가능한 환경문제에 대한 이해가 필요하며, 본 연구에서는 향후 수압파쇄공법에 의한 셰일가스 개발 시 발생할 수 있는 주요 환경 문제들을 정리하고, 이에 대한 해결 방안들을 제시하고자 하였다. This paper discusses important environmental issues that must be considered during shale gas development. Shale gas has been attracting many attention as the next key energy resource with its large abundance through easily accessible production fields, and its lower carbon dioxide & sulfur dioxide emission profile upon combustion when compared to the conventional oil and natural gas resources. Successful development of a shale gas field requires the use of hydraulic fracturing to recover hydrocarbon through the very tight shale formation, which has been frequently associated with environmental contamination issue of water, soil, and atmosphere. Therefore, environmental issues and their solution to minimize environmental impact should be considered for successful development of shale play in a future.

연결감사품질의 결정요인에 관한 연구

최종학(Jong Hag Choi),나경원(Kyoung Won Na),최연식(Youn Sik Choi) 한국경영학회 2009 經營學硏究 Vol.38 No.6

This paper investigates the determinants of audit quality of consolidated financial statements. Given that International Financial Reporting Standards (IFRS) will be introduced to Korea starting from year 2011 and IFRS mandate the use of consolidated financial statements, it would be very important to examine the audit quality of the consolidated financial statements. Up to now, there has been no research at all in Korea which investigates this issue because not consolidated but non-consolidated (i.e., individual) financial statements have been used as primary financial statements. The audit quality is a very important issue in Korean situation which tries hard to enhance corporate transparency and, thus, attracts more local and foreign investments into capital market.This study makes two predictions on the determinants of the audit quality of consolidated financial statements. First, in audit work for consolidated financial statements, the parent company’s auditor may be different from subsidiaries’auditors. In such a case, the auditor of parent company needs to depend on the audits of subsidiary companies performed by another auditors in order to consolidate the financial statements of subsidiaries into those of parent company. In such a case, efficient and effective communications between them could be more difficult. Thus, it might be less expected that information sharing and knowledge spillover occurs during the audit procedures if several different auditors are related to the audit of subsidiary companies. As a results, we expect that the more dependence on other auditors decreases the audit quality of consolidated financial statements.Second, consolidated financial statements represent the parent company and its subsidiaries as one economic entity and, therefore, the complexity of consolidation itself and information asymmetry between the parent company’auditor and its subsidiaries’auditors would increase in proportion with the total number of subsidiaries or the magnitude of transactions between the parent company and subsidiaries or among subsidiaries. So, we expect that the more complexity in consolidation processes decreases the audit quality of consolidated financial statements.This paper measures the dependence on other auditors is measure by the portion of total assets (or sales) audited by other auditors and the number of other auditors. The complexity of consolidation is measured by the total number of subsidiaries or the magnitude of transactions or account receivables and account payables between the parent company and subsidiaries or among subsidiaries. Finally, we employ discretionary accruals estimated by using performance- adjusted modified Jones model (Kasznik 1999; Kothari et al. 2005) in order to proxy for the audit quality. This measure has been used in various prior studies to proxy for accounting or audit quality. This measure has relative advantage compared with other possible measure of audit quality - such as audit opinion, post audit review, or earnings restatement - because this is the only measure that can be applied to general sample of firms whereas other measures are applicable to only a few firms which could be classified into outliers among general samples. In addition, during empirical analyses, we control for the audit quality of individual financial statements in order to emphasize the determinants of consolidated financial statements. For the empirical analyses, we use 1,537 firm-year observations collected over the period from year 2002 to year 2006. These are the firm-year observations that issue both individual and consolidated financial statements and those with all the necessary data are available from KIS-Value Ⅱ database. We perform both univariate and multivariate regression analyses.Empirical results show that the dependence measures (the portion of total assets or sales which are audited by other auditors and the number of other auditors) have significantly positive coeffic