직업병연구에 있어서 시간의존형 폭로변인의 의의

문재동 大韓産業醫學會 1997 대한직업환경의학회지 Vol.9 No.2

Although the final cumulative exposure has been used as a exposure variable on the cohort study for the relation between exposure and disease, the bias from the use of fixed exposure can be developed because the exposure amount changes across the time. We developed the program to handle the Cox model with irregularly changing time-dependent exposure variable and covariates, and the validity about the application of time-dependent exposure variable and lagged interval was practically evaluated by analyzing the data collected for typical retrospective cohort study with that program. The results were as follows : The exposure-response relations between the deaths from lung cancer and exposures(fixed or time-dependent) were not clear when 0 year lagged interval was applied. When 15 years lagged interval was applied, the exposure-response relations between the deaths from lung cancer and the time-dependent exposures to crystalline silica were observed and relative risks increased like 1.00, 1.17, 1.30 and 2.45 across the exposure levels. The relative risk estimates for lung cancer with time-dependent exposure variable were higher than those with fixed exposure variable without regard to the application of lagged interval. The exposure-response relations between the deaths from non-malignant respiratory disease(NMRD) and exposures (fixed or time-dependent) were observed across exposure levels when 0 year lagged interval was applied. When 15 years lagged interval was applied, the exposure-response relations between the deaths from NMRD and the time-dependent exposures to crystalling silica were observed, but were not with fixed exposure variable. The relative risk estimates for NMRD mortality with time-dependent exposure variable were higher than those with fixed exposure variable, and the application of lagged interval on the evaluation of NMRD mortality was meaningless. The results suggest that the application of time-dependent exposure variable on the study of exposure-effect relation should be considered and the application of lagged interval should be decided according to the time needed from disease detection to death.

산업분류별 연구개발의 특허성과 시차분석에 관한 연구 ―국가연구개발사업을 중심으로―

제갈용승 ( Jegal Yongseung ),이지호 ( Lee Jiho ),윤장혁 ( Yoon Janghyeok ) 한국지식재산연구원 2022 지식재산연구 Vol.17 No.3

국가 R&D 투자와 성과 사이에는 시차가 존재한다. 이에 국가 R&D 과제를 활용한 다양한 연구에서는 설문조사, 문헌조사에 기반하여 R&D 투자와 성과 사이의 시차를 정의하였다. 하지만 시차를 정성적인 방법으로 정의한 부분은 모든 선행연구에서 공통적 한계점으로 언급되었으며 시차분석 연구의 필요성이 제시되었다. 이러한 연구 필요성에 기반하여 본 연구는 국가 R&D 특허 성과 데이터와 산업-특허 연계표에 기반한 산업별 R&D 시차분석을 수행하였다. 분석을 통해 산업별로 성과발생 시차를 파악할 수 있었으며, 통계적으로 산업별 시차의 차이가 존재함을 확인하였다. 본 연구의 결과물은 추후 R&D 성과에 대한 평가 시 시차를 반영하는 방법론들에 활용될 수 있을 것이다. 또한 본 연구는 산업별 R&D 성과 발생 시차를 제시하기 때문에 국가기관 및 부처별 정책 입안자가 국가 R&D 사업의 정책과 로드맵을 설정하는 데 유의미한 기초자료로 활용될 수 있다. It is obvious that there is a time lag between a national R&D project and its results(R&D time lag). Previous studies using national R&D data assumed the R&D time lag based on a survey or a literature study, while most of them mentioned the importance of quantifying R&D time lags. For this reason, this study quantifies R&D time lag identification, using Korean national R&D patents and the KSIC-IPC concordance. As a result, R&D time lags by industry were identified and statistical analysis showed that there is a difference in R&D time lag by industry classification. We expect that the research results can be used in R&D policy-related studies that consider R&D time lags among different industries. In addition, policy makers in national institutions can refer to the identified R&D time lags when evaluating national R&D projects or establishing R&D roadmaps.

보건수요와 보건소의 사업간 정책시차 연구

전진숙(Jinsuk Chun),강창현(Changhyun Kang) 경성대학교 사회과학연구소 2015 社會科學硏究 Vol.31 No.1

국민의 건강증진에 크게 기여해 온 보건소는 그동안 중점사업으로 가족계획사업(산아제한정책), 만성질환관리사업, 건강증진사업, 방문보건사업, 정신건강사업, 치매관리사업 등을 지속적으로 확대하여 추진하였다. 보건소는 공공의 제한된 자원을 활용한 관료주의적인 공공보건체계(governmental public health system)의 특성에 따라 정책적 상황에 맞추어 보건의료서비스를 제공해왔다. 이러한 정책들은 시행하는 과정에서 변화가 일어나는 동태적인 측면이 강하기 때문에, 정책수행과정에서 시차는 매우 중요하다. 정책의 시행과정에서 시차의 개념을 원인변수로 보고 사회과학적 인과법칙의 전개과정을 연구하는 시차이론(time-lag theory)을 적용하여 보건소의 사업추진 과정을 검토하였다. 가족계획사업의 경우, 산아제한에 대한 정책수립자들의 인식에는 적시성이 있었지만, 1962년 보건소의 인프라가 제대로 갖추어지지 않은 상태에서 정책을 시행함으로써 작동순서(sequence)에 문제가 발생하여 초기에 사업효과가 나타나지 않는 정책시차를 보였다. 그리고 합계출산율이 대체수준(2.1명) 이하로 하락한 1984년이 아닌 1990년에 산아제한 완화정책을 시행하였고, 저출산의 지속과 심각성에도 불구하고 2000년이 아닌 2006년 출산장려정책으로 전환함으로써 각각 6년간의 인지시차를 보여 타이밍을 놓친 실패한 사업이다. 2003년 본격적인 사업추진에 들어간 만성질환관리사업은 유병률이 높게 나타난 시점(1998년)에 시범사업을 그리고 2001년에 본격적인 사업추진을 하지 않아 2년간의 인지시차를 보였지만 타이밍을 비교적 잘 맞춘 사업이다. 치매관리사업 또한 본격적인 사업추진의 시기가 2000년이 아닌 2005년으로 5년간 지연된 정책시차를 보여 국민의 건강과 사업의 효과성이 떨어졌지만, 미래에 까지 잘 시행해야 할 사업이다. 결론적으로, 지역주민들이 가장 필요로 하는 보건수요에 대한 정책시차를 고려하여 적시성(timing) 있게 보건의료 서비스를 제공한다면, 보건소는 역동적인 기능을 발휘하게 되어 향후 고령사회를 대비할 국민건강의 게이트키퍼(gatekeeper)로서의 역할을 할 것이며, 사회경제적 비용(의료비 및 간접비용)을 감소시킬 수 있을 것이다. The purpose of this study is to examine the health policy needs and the projects of Community Health Center with the time-lag theory in policy studies. In the course of performing health policies, the ‘timing’ is very important in exploring the success of policies. The performance of health service policies can be examined through time-lag theory which has recognition lag and action lag in implementing some projects. Community Health Center, which has made a contribution to promoting the public health of people, has performed lots of health projects such as birth-control policy, chronic disease management, health promotion projects, visiting health programs, mental health service, dementia management project, etc. We try to review whether Community Health Center has performed three critical projects - birth-control policy, chronic disease management and dementia management project ? in right timing or not. According to time-lag approach, birth-control policy missed an appropriate timing because of the wrong sequence between the performance of the policy and the insufficient infrastructure of community health centers. Also, the appeasement policy in 1990s and the fertility promotion policy in 2006 lost the right timing for 5 years respectively. The management of chronic diseases such as hypertension and diabetes showed the relatively appropriate timing for two-year recognition lag. And dementia management project was performed because of five-year action lag, but will be actively provided for preparing the aged society. In conclusion, Community Health Center should try to in time provide existing and future health policies for people in community, considering the effects of the policy time-lag analyzed above.

정책과 제도변화의 시차적 요소

정정길,정준금 서울대학교 행정대학원 2003 行政論叢 Vol.41 No.2

성공적인 정책과 제도변화를 추진하기 위해서는, 개혁추진과 관련된 제도 내외적 요소들을 확인하고 이들이 가지고 있는 시차적 요소들을 분석한 다음 이에 맞는 변화전략을 시기별로 적절하게 사용하는 것이 필요하다. 이에 따라 이 연구에서는 제도나 정책변화에 내재하는 시차적 요소로서, 변화 소요기간, 인과관계의 시차성, 변화의 속도와 안정성, 숙성기간, 선후관계, 적시성, 시간규범 등을 살펴보았으며, 이들 요소들이 제도 및 정책변화 과정에 미치는 영향을 분석하였다. 이 연구를 포함하여 시간적 요소를 중시한 연구들은, 제도개혁과 관련된 조직행태를 설명하고 이해하는 데 새롭고 중요한 분석틀을 제시해 주고, 시간과 관련된 일련의 새로운 독립·종속변수에 대한 관심을 제고시키며, 인과관계 추정의 방법론을 더욱 정교하게 해준다는 점에서 의의를 찾을 수 있다. 제도와 정책변화는 기본적으로 동태적인 성격을 가지고 있으므로, 이를 제대로 파악하여 성공적인 제도개혁의 전략을 마련하기 위해서는, 시간적 요소를 고려하는 시차적 접근을 시도하는 것이 불가피할 것이다. 이 연구를 바탕으로 앞으로 시차적 접근의 이론적 틀을 보다 정교하게 가다듬고 이를 현실 정책사례에 적용함으로써 보다 타당성과 적용가능성이 높은 개혁전략을 제시할 수 있는 연구가 시도되어야 할 것이다. In this article, we propose seven time lag factors of policy change process, each with distinct temporal characteristics, and each with influencing institutional changes. These elements are time for change, temporal causality, pace and stability, maturation, sequence, timing, timing norms. These elements are used to analyze the process of policy and institutional change with a dynamic perspective of time lag. We then argue that large scale change of policy and institution involves multiple temporal elements, thus requiring enactment of multiple strategies considering time factors. This temporal study provides an important frame work for explaining and understanding policy change process, and it focuses our attention on new classes of independent and dependent variables such as time lag factors that provide new theoretical and practical insights. This paper concludes with some suggestions for the further researches which produce more valid and feasible results

Real-Time Traffic Information Provision Using Individual Probe and Five-Minute Aggregated Data

장진환 한국ITS학회 2019 한국ITS학회논문지 Vol.18 No.1

Probe-based systems have been gaining popularity in advanced traveler information systems. However, the high possibility of providing inaccurate travel-time information due to the inherent time-lag phenomenon is still an important issue to be resolved. To mitigate the time-lag problem, different prediction techniques have been applied, but the techniques are generally regarded as less effective for travel times with high variability. For this reason, current 5-min aggregated data have been commonly used for real-time travel-time provision on highways with high travel-time fluctuation. However, the 5-min aggregation interval itself can further increase the time-lags in the real-time travel-time information equivalent to 5 minutes. In this study, a new scheme that uses both individual probe and 5-min aggregated travel times is suggested to provide reliable real-time travel-time information. The scheme utilizes individual probe data under congested conditions and 5-min aggregated data under uncongested conditions, respectively. As a result of an evaluation with field data, the proposed scheme showed the best performance, with a maximum reduction in travel-time error of 18%.

R&D 투자와 특허간의 시차효과 분석 - 기술수준에 따른 산업분류를 중심으로 -

송지현 ( Ji-hyun Song ) 한국생산성학회 2018 生産性論集 Vol.32 No.2

Research and development is generally considered the driving force of innovation. Innovation is a crucial factor for firms in terms of industrial competitiveness and economic growth as it directly impacts firm productivity and further R&D activities. However, due to the uncertainty of R&D results, R&D strategy needs to choose the timing of investment. Many studies have shown that there is a close relationship between R&D expenditure and patents, but these have not been studied at a technical level. This study aims to empirically estimate distributed lag effects between R&D investment and patent by industry and firm size. To analyze the lag structure between them, we used a dataset of the “Business Activity Survey” compiled by Statistics Korea from 2006 to 2015 and employed a polynomial distributed lag model. This is because it is highly likely that multicollinearity will emerge, if a distributed lag model is applied to multiple regression analysis. R&D expenditure and the number of patents held were used to measure R&D input and output, respectively. The main results are as follows. First, the empirical results indicate the presence of bilateral causality between R&D expenditure and patents (R&D→Patents; R&D←Patents). Our data indicate that the traditional causality is stronger although the reverse causality is also acceptable. Second, the time-lag between R&D investment and patent application was three years. Third, we found that there are differences among industries with a similar level of technology with regard to the time-lag effect. In particular, high technology industries have a longer time-lag than other industries. These results are similar to previous studies that suggested industries with higher technology levels determine long-term investments. Finally, medium-sized firms have a shorter time-lag between R&D investment and patents than that of large or small firms. This study would be a new approach using technology level, which would be able to provide a benchmarking idea to firm owners and policy makers. Firm owners have to control their input effectively, sometimes reducing or transferring resources such as R&D investment and employees according to many factors such as technology level, size, and so on. Attempting to predict the size and timing of R&D results is an effective way of responding to the uncertainty of the R&D and to reduce the management risk before making decisions regarding R&D investment.

고속도로 기종점 간 통행시간 예측모형 개발

김주영 한국교통연구원 2009 交通硏究 Vol.16 No.2

The O-D(origin-destination) travel time on freeway is important information for users to select the departing time, traveling path and for operator to decide the strategies for congestion management of freeway during the holiday which the travel demand increases. It is so difficult to predict the O-D travel time accurately because of variation of the O-D demand and the departure time. The freeway of Korea is equipped with the VDS (vehicle detector system) which is capable of collecting the real-time traffic information such as the spot speed, traffic flow, and occupancy. Also the TCS (toll collection system) allows the operator to collect the real-time O-D travel time based on the arrival time. The travel time should be informed to users based on the current departer and two kind of methods using VDS data and TCS data are used to calculate the O-D travel time. The former generates the error in the gathering process from section to O-D travel time and the latter generates the error from the time-lag between departure and arrival. In this paper, the new empirical model for estimating the O-D travel time is proposed using both of VDS and TCS data to assist the shortcoming each other. The proposed model was evaluated using the real traffic data of Chuseok last year which occurred serious congestion and conduced much better accuracy than the existing methods. In the conclusion, we suggest the improving technique of the proposed model as future study. 고속도로 기종점 간 통행시간은 이용자의 출발시간대 및 노선선택, 그리고 도로 운영자의 의사결정 등에 활용되는 유용한 교통정보이다. 특히 교통수요가 집중되어 극심한 교통혼잡이 발생하는 추석 및 설 연휴기간 동안의 기종점 간 통행시간 예측은 교통수요가 가변적이어서 정확히 예측하기에 많은 한계점이 있다. 우리나라 고속도로는 ㎞ 단위로 교통정보 수집체계인 VDS가 구축되어 실시간 교통정보 수집이 가능하며, 또한 TCS 자료를 이용하여 도착시각 기반 기종점 간 통행시간의 수집이 가능하다. 이용자를 위한 출발시각 기준 통행시간을 예측 · 제공하기 위한 기법으로 현재 시각 기준의 VDS 자료를 이용하는 기법과 현재 도착시각 기준의 기종점 간 통행시간인 TCS 자료를 이용하는 기법이 있는데, 전자는 구간 통행시간을 기종점으로 합산하는 과정에서의 오차와, 후자는 도착시각과 출발시각 간의 시간처짐현상(time-lag)에 따른 오차로 인하여 예측력에 한계가 있는 것으로 나타났다. 본 연구에서는 실시간으로 수집가능한 VDS 자료와 TCS 자료를 병합하여 기존의 2가지 통행시간 예측기법의 단점을 보완하는 기종점 간 통행시간 예측기법을 제안하고, 2007년 설 및 추석 연휴기간 동안의 서울-북대구 영업소 간 실제 통행시간을 이용하여 평가하였다. 제안된 모형은 기존의 2가지 통행시간 예측기법보다 정확도가 더욱 높은 결과를 보여주고 있으며, 시간처짐현상을 보완하기 위한 새로운 기법을 향후과제로 제안하고 있다.

A Multi-Period Input DEA Model with Consistent Time Lag Effects

정병호,장연상,이태한 한국산업경영시스템학회 2019 한국산업경영시스템학회지 Vol.42 No.3

Most of the data envelopment analysis (DEA) models evaluate the relative efficiency of a decision making unit (DMU) based on the assumption that inputs in a specific period are consumed to produce the output in the same period of time. However, there may be some time lag between the consumption of input resources and the production of outputs. A few models to handle the concept of the time lag effect have been proposed. This paper suggests a new multi-period input DEA model considering the consistent time lag effects. Consistency of time lag effect means that the time delay for the same input factor or output factor are consistent throughout the periods. It is more realistic than the time lag effect for the same output or input factor can vary over the periods. The suggested model is an output-oriented model in order to adopt the consistent time lag effect. We analyze the results of the suggested model and the existing multi period input model with a sample data set from a long-term national research and development program in Korea. We show that the suggested model may have the better discrimination power than existing model while the ranking of DMUs is not different by two nonparametric tests.

국가연구개발사업의 학술적 성과의 시차효과에 관한 실증적 연구

정병호(Byung-Ho Jeong),천강민(Kang-Min Cheon),양재경(Jaekyung Yang) 한국산업경영시스템학회 2012 한국산업경영시스템학회지 Vol.35 No.1

This study examines the relationship between R&D investment and subsequent outputs of the research activity. Usually, there is some time difference between the production of research outputs, such as academic papers and application or registration of patents, and the investment of R&D expenditure. The time lag for producing this kind of research outputs should be considered to evaluate the performance of research activity exactly. The purpose of this study is to identify time lag effect between the times of input and output of a R&D activity and to derive the degree of time lag using the data set of a long term R&D program supported by Korean government. A modified Almon model is suggested to identify the time lag effect between input and output of research activities performed by this program. Time-series cross-section data from 16 research centers between 2001 and 2009 are used to find time lag effect.

운영 DB데이터 분석을 통한 G4C 전자정부 정보화 사업 투자 시차효과 분석

조남재(Nam Jae Cho),임규건(Gyoo Gun Lim),이대철(Dae Chul Lee) 한국데이타베이스학회 2009 Journal of information technology applications & m Vol.16 No.4

Considering time-lag in the performance evaluation of information system (IS) investment is important because its effect reveals after certain period of time passed. Particularly it is more in the systems of e-government informatization projects which the amount of investment and the scale of business are huge. Many methods to solve this issue have been proposed such as system dynamics methods, simulations, structural equations etc. However, it is still difficult and unsolved problem because collecting practical data for time-lag analysis is very hard. In this paper, we analyze IS time-lag effect through factor analysis using the accumulated practical operational DB data. For the performance evaluation of the G4C system, the representative e-government web portal, we selected eleven factors reflecting time passing in G4C DB data. With these factors this paper conduct time-lag analysis in four view points. First, we conducted 'Stabilizing of G4C system' and got a result that IS is needed about three years for the stabilization. Second, we conducted 'Utilization of G4C system' and got a result that the utilization reaches appropriate level after in three years later after the introduction of G4C system. Third, we conducted 'Cost reduction effect' and got a result that cost reduction is stable in the third year after the introduction of G4C system. Lastly, we conducted 'System maturity effect' and got a result that the system reaches to the quality level that users expect after third to fourth years. According to the results of this research, we found that performance of IS improv continuously not immediately, and it needs three or four years of time-lag.