가상 절점을 이용한 적층 구조물의 페리다이나믹 층간 결합 모델링 검토

안태식,하윤도,Ahn, Tae Sik,Ha, Youn Doh 한국전산구조공학회 2017 한국전산구조공학회논문집 Vol.30 No.5

결합 기반 페리다이나믹 모델은 취성재료의 동적파괴 해석에 많이 이용되고 있으며, 최근의 연구(Bobaru et al., 2012)를 통해 적층유리 구조물의 동적 파괴 패턴 분석에도 활용되었다. 특히 실험(Bless et al., 2010)에서 나타난 적층유리 구조물의 다양한 손상 형태(압축 영역, Floret, Hertz-type 균열 등)를 결합 기반 페리다이나믹 시뮬레이션을 이용하여 구현하였다. 그러나 실제 적층 구조물은 각 유리판 사이를 탄성이 있는 층간 재료로 결합하는 반면, 기존의 페리다이나믹 수치 시뮬레이션에서는 층간 재료 결합을 무시하고 각 유리판이 직접 결속되도록 가정하여 층간 재료 효과가 무시되었다. 본 연구에서는 페리다이나믹 층간 재료 모델링을 통해 실제 적층 구조물에 보다 근접한 페리다이나믹 수치 해석 모델을 제안한다. 일반적으로 층간 재료는 매우 얇기 때문에 층간 재료를 명시적으로 모델링할 경우 많은 해석시간과 메모리가 소모되어 비효율적이다. 따라서 본 연구에서는 명시적 모델링을 대신하여 가상 절점을 통해 층간 재료를 모델링한다. 수치 예제를 통해 제안된 층간 재료 모델링의 효율성 및 정확성을 검토한다. 또한 압축 상태의 적층 구조물 해석을 위해 단거리 상호작용력에 기반한 투과 방지 기법을 도입하고 파라미터 테스트를 통해 검증한다. Peridynamics has been widely used in the dynamic fracture analysis of brittle materials. Recently, various crack patterns(compact region, floret, Hertz-type crack, etc.) of multilayered glass structures in experiments(Bless et al. 2010) were implemented with a bond-based peridynamic simulation(Bobaru et al.. 2012). The actual glass layers are bound with thin elastic interlayer material while the interlayer is missing from the peridynamic model used in the previous numerical study. In this study, the peridynamic interlayer modeling for the multilayered structures is proposed. It requires enormous computational time and memory to explicitly model very thin interlayer materials. Instead of explicit modeling, fictitious peridynamic particles are introduced for modeling interlayer materials. The computational efficiency and accuracy of the proposed peridynamic interlayer model are verified through numerical tests. Furthermore, preventing penetration scheme based on short-range interaction force is employed for the multilayered structure under compression and verified through parametric tests.

다양한 박막을 증착한 디젤 엔진용 피스톤링과 실린더 블록의 마찰 마멸 및 스커핑 수명 평가

안태식,조대현,정순오,이영제,Ahn, Tae-Sik,Cho, Dae-Hyun,Oh, Chung-Soon,Lee, Young-Ze 한국트라이볼로지학회 2007 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.23 No.4

Wear and scuffing tests were conducted using friction and wear measurement of piston rings and cylinder blocks in low friction diesel engine. The frictional forces, wear amounts and cycles to scuffing in boundary lubricated sliding condition were measured using the reciprocating wear tester. The cylinder blocks were used as reciprocating specimens, and the piston rings with several coatings were used as fixed pin. Several coatings were used such as DLC, TiN, Cr-ceramic and TiAlN in order to improve the tribological characteristics. From the tests wear volume of piston ring surfaces applied various coatings were compared. During the tests coefficients of friction were monitored. Test results showed that DLC coatings showed good tribological properties. TiN and Cr-ceramic coated rings showed good wear resistance properties but produced high friction.

영업의 개황을 통한 자발적 공시의 결정요인 -한국 기업에 대한 실증 연구

안태식 ( Tae Sik Ahn ),이정훈 ( Jung Hun Lee ) 한국회계학회 2005 회계학연구 Vol.30 No.-

This study examines the economic determinants of voluntary disclosures in the ``Overview of Operations`` section of the published annual report. The overview disclosures in Korea provide a unique setting for testing the economic motives of voluntary disclosures because there are no explicit regulations for the overview contents and format in Korea. We measure the level of voluntary disclosures by the number of words and the frequency of value-related keywords in an overview disclosure. We find that the levels of overview disclosure are positively associated with the degree of external financing, industry concentration, firm size, ownership of minority investors, and top management`s involvement in the overview disclosures. Meanwhile, we find no consistent association between the level of overview disclosure and firm performance, ownership of largest/institutional/ foreign shareholders, return volatility, return-earnings correlation, and leverage. We find less significant associations when we use change variables instead of level variables or when we control for industry membership. Our results suggest that managers use the overview of operations as an information medium to communicate value-related information to the stakeholders even in the absence of mandatory requirements for the narrative disclosures.

단위의료행위원가 추정 방법론의 개발과 적용

안태식(Tae Sik Ahn),오동일(Dong Il Oh),정형록(Hyung Rok Jung) 한국경영학회 2004 經營學硏究 Vol.33 No.1

`Conversion factor` in medical industry is fee for the unitized medical service. Conversion factor is multiplied by relative value of medical service, called RBRVS(Resource-Based Relative Value Scale), to determine the medical service charges. This research develops various estimation methodologies for conversion factors and applies them to Korean hospital cost data to determine sensitivities of methodologies, and to calculate the differences in conversion factors among different types of medical care institutions. Moreover, relationships between size of hospitals and their conversion factors estimated for individual medical care institutions are analyzed. According to our result, larger hospitals such as university hospitals show higher conversion factors as predicted. We also observed significant differences of conversion factors among different classes of institutions. This result indicates that current `adjustment factor` used to adjust the cost structure differences among different classes of institutions does not fully reflect the actual cost structure differences among different classes of institutions. Our result also showed that even within the same type of medical institutions supposedly with same cost structure, large differences of conversion factors are observed indicating the efficiency differences among institutions.

연구논문 : 정부계약 원가검증 기간의 결정요인 및 성과

안태식 ( Tae Sik Ahn ),이상희 ( Sang Hee Lee ),현정훈 ( Jeong Hoon Hyun ),김동욱 ( Dong Uk Kim ) 한국회계학회 2013 회계저널 Vol.22 No.5

2008년말부터 시작된 글로벌 금융위기를 극복하기 위한 경기부양 정책의 일환으로, 정부는 재정 조기집행을 시행하고 있다. 이를 위해서는 계약의 조기 체결이 이루어져야 하고, 계약체결의 절차 중 병목 역할을 하는 원가검증 기간의 단축이 뒷받침되어야 한다. 그러나 제한적인 자료 접근성 때문에 원가검증 기간의 결정요인은 무엇이며, 원가검증 기간 단축이 의도한 성과를 내는지에 대한 연구는 부족하다. 본 연구는 군수물자를 주도 조달하는 정부기관의 실제 원가검증 자료를 활용하여 원가검증 기간의 결정요인과 그 성과에 대해서 분석하였다. We examine the determinants and performance effects of cost verification period in government contracts by using actual dataset from the Defense Acquisition Program Administration. Our empirical results show that cost verification period increases when cost analysis method is used, negotiating contract type is used, and contract amount is larger. Moreover, when the military materials are procured and costing managers` workloads are higher, the cost verification period also increases. These findings support hypothesis derived from information asymmetry and political cost. Our results also indicate that the cost verification period has positive effects on cost estimating performance. As cost verification period increases, both probability of contract success and budget reduction ratio increase. Our results have practical implications for government contracts` managers by indicating that reduced costing period can lead to lower cost reduction ratio and lower success possibility in bidding. To improve the efficiency of government contracts, the government regulators need to draw up measures to support costing managers` job specification depending on contract types, contract amounts and workload.

Does Sales Commission Affect the Sales Mix? : Evidence from an Automobile Distribution Company

Tae-Sik Ahn(안태식),Jin-Ha Park(박진하),Hye-Jeong Nam(남혜정),Hyung-Rok Jung(정형록) 한국관리회계학회 2010 관리회계연구 Vol.10 No.1

연공주의에 입각하여 설계되었던 기존의 보상체계와는 달리 종업원 보상에 있어서 성과급의 비중이 커져가고 있음에도 불구하고, 성과급 제도의 도입에 따른 효과를 다룬 실증연구는 매우 드문 실정이다. 본 연구는 우리나라 자동차판매회사의 2000년부터 2004년까지의 매출 및 판매수수료 자료를 토대로 수수료가 판매사원의 매출배합에 미치는 영향에 대해 연구하였다. 그 결과, 판매사원이 여러 가지 차종을 판매할 수 있는 환경에서 차종별 수수료의 차이가 커졌을 때, 수수료가 가장 높은 차종의 매출 비율을 증가시키는 것이 관찰되었다. 한편, 성과급제도 도입이전에 수당이 가장 높은 차종의 판매비율이 낮았던 판매사원의 경우 위의 결과가 더욱 현저하였다. 이러한 결과는 수당이 높은 차종을 선호하는 판매사원의 경우 이미 최선을 다하고 있었기 때문에 매출배합을 변화시킬 여지가 없었거나, 혹은 그렇지 않았던 판매사원들이 성과급제도 도입 이후 매출배합을 변화시키면서 수수료가 높은 차종의 판매경쟁을 심화시켰기 때문인 것으로 추측된다. 종합하면, 성과급제도는 종업원의 목표와 회사의 목표를 일치시켜, 회사가 종업원의 행동을 전략적으로 변화시키는 데 효과적인 것으로 판단된다. This study examines whether employees are more likely to allocate their effort to selling products that carry a higher commission following the implementation of a commission system. Although performance-based compensation is widespread, empirical evidence of its effect on employee behavior is scant. Using 17,709 individual-level data from 2000 to 2004 in an automobile distribution company that implemented a commission system in 2002, this study investigates the effect of sale commission on the sales mix. The results show that employees allocate more effort to cars with the highest expected sales commission in their particular sales mix when commission varies widely across products. This finding provides empirical evidence that placing a higher commission on a specific product enhances the sales of that product in a multi-product setting, and also suggests that the effect of a commission system is more significant for employees whose sales mix before the implementation of the system had a smaller proportion of the products with the highest expected sales commission. In conclusion, it is proposed that commission systems are effective in strategically directing the behavior of employees and consequently achieving goal congruence between a firm and employees.

한국제조기업의 비대칭적 원가행태

안태식(Tae Sik Ahn),이석영(Seok Young Lee),정형록(Hyung Rok Jung) 한국경영학회 2004 經營學硏究 Vol.33 No.3

BSC 성과측정지표간의 인과관계

안태식 ( Tae Sik Ahn ),정형록 ( Hyung Rok Jung ),박경호 ( Kyung Ho Park ) 한국회계학회 2008 회계저널 Vol.17 No.3

성과평가시스템에서의 목표설정

안태식 ( Tae Sik Ahn ),최연식 ( Youn Sik Choi ),권대현 ( Dae Hyun Kwon ) 한국회계학회 2011 회계학연구 Vol.36 No.1

본 연구는 우리나라 주요 공공기관의 경영실적평가 자료를 이용하여 성과평가제도안에서 목표설정이 어떻게 이루어지고 있는지를 다양한 실증모델을 통해 분석하였다. 첫째, 피평가자의 차기 목표달성확률이 당기에 목표를 달성했는지 여부에 따라 차이가 있음을 발견하였는데, 이는 피평가자의 성과목표를 설정할 때 과거성과를 완전히 반영하지 않는 것을 의미한다. 둘째, 목표설정 시 톱니현상(ratchet principle)의 존재 여부에 대한 분석 결과, 전체표본에서는 차기목표가 당기성과를 기준으로 설정되었으나, 당기의 목표달성 여부에 따라 당기성과가 차기목표에 반영되는 정도는 다르지 않았다. 목표설정방법을 구분한 분석에서는 추세치, 목표부여 및 목표대실적에서 모두 톱니현상이 발견되었는데, 특히 목표부여 지표에서는 당기 목표미달 시 차기목표가 증가하는 현상이 발견되었고 목표대실적 지표에서는 하방탄력적 톱니현상이 나타났다. 셋째, 차기목표의 결정요인을 분석한 결과 목표달성여부, 그리고 목표초과달성도가 차기목표 설정에 중요하게 고려되고 있으나, 목표향상도는 중요하게 고려되지 않는 것으로 나타났다. 목표달성여부만 고려할 경우에는 성과개선도가 차기 목표결정의 중요한 요인으로 나타나지만, 목표초과달성도를 추가로 고려한 경우에는 성과개선도의 중요성은 사라지는 것으로 나타났다. 본 연구에서 목표설정과정에 피평가자가 참여하는 정도에 따라 톱니현상이 다르게 나타나는데, 이는 정보우위에 있는 피평가자가 목표설정에 보다 깊이 참여할수록 차기목표가 달성하기 쉽도록 설정될 가능성이 크다는 것을 시사한다. 또한 공공기관의 경영평가제도에서 지속적 성과개선 보다는 일시적 성과개선을 유도하거나 정부정책 및 거시경제 상황을 반영하는 목표설정이 일어날 가능성을 시사한다. How to set targets is a crucial factor in the successful implementation of performance-evaluation and compensation plans. The primary use of targets is to coordinate the allocation of resources and to evaluate performance (Ittner and Larcker 2001; Leone and Rock 2002). Targets are also a key component of management control systems; the way firms set targets, the way they revise them over time, and the ease with which ratees achieve those targets affect their incentives to increase firm value (Indjejikian and Nanda 2002). More challenging targets lead higher performance by motivating employee to be more productive (Stedry 1960; Stedry and Kay 1966; Rockness 1977; Chow 1983). The first-best strategy to maximize firm value may be to set a target that approximates employees` true capability. Though target-setting is important and pervasive in performance-evaluation system, evidence concerning target-setting practice is scant because researchers rarely have access to such inherently firm-specific and often confidential internal information (Ittner and Larcker 2001). This paper investigates how targets are set by using a variety of empirical models coupled with performance evaluation data of the Korean Government-owned enterprises (GOEs). First, we follow the simple framework developed by Indjejikian and Nanda (2002), which assume that a firm`s executive works for two periods and the firm rewards the executive based on a measure of his performance evaluated relative to a target. This framework also assume that a target depends only past targets and past performance. Thus, under the framework, if the firm does not adjust the target for the executive`s past performance, then target at any period is timeless and does not depend on prior period`s performance. We provide empirical evidence that ratees` chance of achieving their targets depend on whether the ratees` performance exceeded their targets in the previous year. This findings suggest that raters do not adjust targets to fully reflect ratees` past performance. Second, we examine whether the ratchet principle is implemented in the performance evaluation system of Korean GOEs. The ratchet principle is the well-known tendency of raters to use current performance as a criterion for determining future targets (Weitzman 1980). Given the uncertainty about the true performance capability of ratees, raters regard the performance in any period as the revealed minimal level of their capabilities in the next period (Berliner 1976). Therefore, in a principalagent setting, the ratchet principle is adopted if contracts explicitly or implicitly reflect past performance information because performance information reduces the variance with which future performance is measured (Milgrom and Roberts 1992). We find a symmetric ratchet principle for performance measures of which targets are revised by a formula, and a super-variable ratchet principle for performance measures of which targets are set by ratees` participation. Surprisingly, targets for the next year increases rather than decreases when ratees miss targets at any period for performance measures of which targets are endowed by raters. Finally, we investigate the determinants of next period`s targets in order to establish that firms design targets to motivate their executives optimally. Leone and Rock (2002) consider two determinants, whether or not and how much ratees` beat (or meet) targets. Besides them, we additionally examine how much performance at any period increase compared to prior period`s performance and how much targets at any period change compared to prior period`s targets. We find that whether or not and how much ratees` beat (or meet) targets are significant determinants of target-setting, while change in target is insignificant. In addition, change in performance has an influential effect on the next period`s target-setting when the fact whether ratees` beat (or meet) targets or not is considered. However, we find that change in performance is no longer significant when the fact how much ratees` beat(or meet) targets is additionally included in the regression model. Our findings that ratcheting pattern depends on the degree of ratee`s participation in the target-setting process suggest that the more ratees participate in targetsetting, the more easily achievable targets seem to be set. They also imply that the current GOEs` target-setting mechanism may induce temporarily improved performance rather than persistent innovation in performance.

노동조합이 기업의 공정공시에 미치는 영향에 대한 연구

안태식 ( Tae Sik Ahn ),심호식 ( Ho Shik Shim ),박진하 ( Jin Ha Park ) 한국회계학회 2011 회계학연구 Vol.36 No.4

개요: 본 연구에서는 노동조합이 기업에서 공정공시를 통해 발표하는 정보의 빈도에 미치는 영향을 조사하였다. 연구 분석 결과 평균적으로 유노조기업은 무노조기업에 비해 공정공시의 빈도가 낮으며, 유노조기업만을 대상으로 볼 때는 노동조합가입률이 높을수록 공정공시의 빈도가 높은 것으로 나타났다. 상기의 결과는 (1) 유노조기업의 경영진은 노동조합과의 단체교 섭에서 유리한 위치를 점유하기 위하여 무노조기업에 비해 공정공시를 덜 하려는 유인이 있으며, 노동조합의 존재만으로는 기업의 투명경영을 제고하고 공정공시대상정보의 생산 및 유통을 촉구하는 역할을 수행하는데 한계가 있으나, (2) 노동조합의 협상력이 강해지면, 투명경영에 대한 요구 및 공정공시대상정보의 대내외적 증가를 통해 공정공시 빈도가 증가하게 되는 것으로 해석될 수 있다. 본 연구를 통해 노동조합이, 전통적인 노사관계론의 영역을 넘어, 기업의 공시전략에 미치는 영향에 대한 이해를 보다 풍부하게 할 수 있다. 또한 국내의 노동조합 연구는 미국의 산업별자료가 아닌 기업별 자료를 기반으로 수행되므로 노동조합의 존재유무와 관련된 내생성 문제를 직접적으로 통제하여 발생 가능한 측정오류를 줄일 수 있다. 마지막으로, 실무에서는 노동조합이 기업의 정보제공수준에 영향을 미칠 수 있다는 점을 인지하여 투자결정을 해야 함을 시사한다. This study examines the relationship between labor union and the frequency of information disclosed under fair disclosure system. Specifically, we investigate whether the presence of union (bargaining power of unions) is related to the frequency of disclosure. There exist two different perspectives on the role of unions in a union-management relationship: a partner for goal alignment or a residual claimant. The former view emphasizes that management can achieve effective labor-management cooperation and goal alignment with unions by sharing information (Palmer 1977; Foley and Maunders 1977). However, the latter perspective stresses that unions, through collective bargaining, redistribute a larger portion of profits to their members and consequently decrease firm profitability. In other words, in a situation where the firm and the union share the profits, the union would attempt to maximize the utility of its members by increasing its share of the firm`s surplus. Therefore, firms with a unionized workforce should have an incentive to hide or misrepresent their true position to take advantage of the negotiation (Reynolds et al. 1998). In this regard, studies have suggested that unionized firms carry out a lower level of investments (Bronars and Deere 1993; Fallick and Hassett 1999), use accounting choice to influence labor negotiations (DeAngelo and DeAngelo 1991; D`Souza et al. 2001; Yoon and Ko 2006), increase debt (Bronars and Deere 1991; Matsa 2010), or hold smaller cash reserves (Klasa et al. 2009). However, there is little evidence concerning whether a firm conceals information to its union except Hilary (2006) which finds empirical evidence of a positive relationship between strong organized labor forces and information asymmetry. Thus, the purpose of our study is to enhance understanding on this issue by examining the relationship between labor union and the frequency of disclosure. We investigate corporate disclosures following the adoption of regulation fair disclosure of the Korea Stock Exchange (KSE) in November 2002. Disclosures under this rule are voluntary in terms of that the firm has discretion over whether to release the information or not (Shim et al. 2010). Therefore, this provides a good environment to investigate a firm`s strategy on disclosure when they have an organized labor force. We develop our hypotheses based on two competing effects of union. On the one hand, managers of a firm may have an incentive to reduce information when the uncertainty concerning managerial objectives is higher. Strong labor provides this environment because managers act differently in the presence of different parties that have potentially conflicting goals. For example, while managers would manipulate earnings upward in general, those facing strong union would manipulate earnings downward, and thereby misrepresent their true position to be better off both in the market and in labor negotiation. From this perspective, unionized firms may have an incentive to minimize disclosure and increase uncertainty in order to increase their bargaining power in collective bargaining. On the other hand, unions argue that not only they are residual claimant but also they enhance the information environment by discipline firms to report the firm`s financial condition faithfully and to disclose that information to the market. In addition, information required by union is overlapped with the regulation fair disclosure, and KSE`s guideline propose firm to disclose information that is internally distributed if it is a subject of regulation fair disclosure. The more strong the union is, the bigger this effect will be. Therefore, from the second perspective, it is expected that the frequency of disclosure is higher in the presence of strong union. We do not predict whether the relationship between labor union and the frequency of disclosure is positive or negative because there are competing arguments. On the one hand, as we discussed above, a strong union could reduce the frequency of disclosure because firms have an incentive to minimize information flow both to them and to the market. On the other hand, a strong union could demand for more information disclosure both to them and to the market resulting in a higher frequency of the disclosure. Following these two competing arguments, we posit our hypotheses in null form that the presence of union (bargaining power of unions) is not related to the frequency of disclosure. Our sample consists of 1,681 firm-year observations in the manufacturing industry for the period 2003-2008. All firms are listed on the KSE. Using this sample, we find that unionized firms have lower frequency of fair disclosure compared to nonunionized firms. Second, we find that union`s bargaining power is positively related to the frequency of fair disclosure. In sum, this result implies that the existence of a union reduces the firm`s level of fair disclosure, but in a unionized firm, the stronger the union, the higher frequency of fair disclosure because union can play a monitoring role. This study has implications to practitioners and academics on labor negotiations and disclosure. In addition, we try to eliminate the endogeneity problem that arises from the characteristic differences between unionized firms and non-unionized firms using Heckman`s two-step regression (1979). Finally, the paper utilizes firmlevel union data uniquely available in Korea.