• Journal of Gastric Cancer
• /
• v.7 no.1
• /
• pp.1-8
• /
• 2007

Purpose: There has been increased the number of early gastric cancer and laparoscopy-assisted gastrectomy (LAG), due to early detection through mass screening program. We started the LAG in April 2004 and performed 119 cases of gastric cancer in 2005, so we report a surgical outcome compared with that of open gastrectomy (OG). Materials and Methods: 119 patients underwent LAG in 2005, and for open group, 126 patiens of early gastric cancer were selected sequentially from January 2005 to March 2005. We compared clinicopathologic characteristics, postoperative courses and complications between two groups. Results: There was no significant difference between age, a length of hospital stay, distal resection margin and a number of retrived lymph nodes. The operation time was longer in LAG group (239.2 vs 123.3 mins, P<0.001) and a diet progression was faster in LAG group (first flatus: 3.05 vs 3.70 days, SOW: 2.86 vs 3.22 days, liquid diet: 3.87 vs 4.19 days, soft diet: 4.84 vs 5.26 days, P<0.001). But there was no difference statistically in postoperative discharge date (7.73 vs 8.25 days, P=0.229). The additional requirement of analgesic injection was less frequent in LAG group (2.97 vs 4.92 times, P<0.001). The harvested lymph nodes were similar in both groups (23.9 vs 23.1, P=0.563). A complication rate was lower in LAG group (4.9% vs 9.5%), but there was no statistical significance (P=0.179). There was no mortality in both groups and no conversion to open gastrectomy in the LAG group. Conclusion: LAG can be performed safely and accepted in view of curative procedure in treatment of early gastric cancer. But we need the follow up of long-term period to evaluate the survival rate and recurrence, and a prospective randomized controlled study should be done to establish that LAG will be a standard operation for early gastric cancer.

• The Korean Journal of Applied Statistics
• /
• v.29 no.1
• /
• pp.243-255
• /
• 2016

The developed composite index has limits to estimate and predict economic status due to economic pattern change and the response change of explanatory variables. A higher precedence individual indicators should be selected to predict the future accurately. In this study, effectiveness of Jeju Island precedence indicators consists of constituents in the area, the consumer price index, services production index, mining and manufacturing production index. The average temperature of Seogwipo and credit card purchase amount is reviewed as an economic turning point consideration and time lag correlation analysis with real data. In addition, we suggest the proper reference cycle in Jeju composite precedence index and evaluate the configuration in leading indicators for Jeju by comparing national economic indicators. Based on the derived results, the current problems of Jeju Island precedence indicators will be illustrated and the improvement methods to estimate a regional composite index will be suggested.

• Healthcare Informatics Research
• /
• v.24 no.4
• /
• pp.300-308
• /
• 2018

Objectives: Prompt detection is a cornerstone in the control and prevention of infectious diseases. The Integrated Disease Surveillance Project of India identifies outbreaks, but it does not exactly predict outbreaks. This study was conducted to assess temporal correlation between Google Trends and Integrated Disease Surveillance Programme (IDSP) data and to determine the feasibility of using Google Trends for the prediction of outbreaks or epidemics. Methods: The Google search queries related to malaria, dengue fever, chikungunya, and enteric fever for Chandigarh union territory and Haryana state of India in 2016 were extracted and compared with presumptive form data of the IDSP. Spearman correlation and scatter plots were used to depict the statistical relationship between the two datasets. Time trend plots were constructed to assess the correlation between Google search trends and disease notification under the IDSP. Results: Temporal correlation was observed between the IDSP reporting and Google search trends. Time series analysis of the Google Trends showed strong correlation with the IDSP data with a lag of -2 to -3 weeks for chikungunya and dengue fever in Chandigarh (r > 0.80) and Haryana (r > 0.70). Malaria and enteric fever showed a lag period of -2 to -3 weeks with moderate correlation. Conclusions: Similar results were obtained when applying the results of previous studies to specific diseases, and it is considered that many other diseases should be studied at the national and sub-national levels.

• Advances in environmental research
• /
• v.4 no.2
• /
• pp.83-104
• /
• 2015

Air Quality Index (AQI) is a pointer to broadcast short term air quality. This paper presents one day ahead AQI forecasting on seasonal basis for three major cities in Maharashtra State, India by using Artificial Neural Networks (ANN) and Genetic Programming (GP). The meteorological observations & previous AQI from 2005-2008 are used to predict next day's AQI. It was observed that GP captures the phenomenon better than ANN and could also follow the peak values better than ANN. The overall performance of GP seems better as compared to ANN. Stochastic nature of the input parameters and the possibility of auto-correlation might have introduced time lag and subsequent errors in predictions. Spectral Analysis (SA) was used for characterization of the error introduced. Correlational dependency (serial dependency) was calculated for all 24 models prepared on seasonal basis. Particular lags (k) in all the models were removed by differencing the series, that is converting each i'th element of the series into its difference from the (i-k)"th element. New time series is generated for all seasonal models in synchronization with the original time line & evaluated using ANN and GP. The statistical analysis and comparison of GP and ANN models has been done. We have proposed a promising approach of use of GP coupled with SA for real time prediction of seasonal multicity AQI.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.30 no.4
• /
• pp.15-25
• /
• 2005

As implied by the terms of IT productivity Paradox, measuring the Information technology contribution to economic performance has been one of the challenging issues to both policy makers and business professionals. As such, diverse attempts with sophisticate analyses have been reported in the literature to analyze the effect of IT contributions. In this paper, we follow Growth Accounting Method to measure the IT contribution effect to manufacturing firm's economic performance in Korea. Various regression methods and statistical analyses are applied with fourteen years of industry Panel data. Using the Cobb-Douglas function, time lag analysis is made to understand IT effect to economic growth. Instead of capturing data from individual firm, industry level data from the National Statistics Bureau is used for IT capital, non-IT capital, and so on. Statistical analysis following the panel unit test and Panel co-integration test was performed to reveal the exact effect of IT contribution to economic performance. Empirical testing results for non-stationary nature of IT investment effect are reported as well as IT contribution to manufacturing industry's economic performance.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1978.06a
• /
• pp.5.2-6
• /
• 1978

The prognosis of the laryngeal diseases is highly dependent on the early diagnosis and treatment. The biopsy finding is inevitable for the cofirmed diagnosis. A clinico-statistical survey of the biopsy result of the larynx in 142 cases was done at the Department of the Otolaryngology Seoul National University Hospital during a period of 3 yrs from 1973 to 1975. Results are as follows 1. Of the 142 cases, 109 cases (76.8%) were males and 33 cases (23.2%) females. Sex ratio was 3.3 : 1. 2. Age distribution shows 41 cases (28.8%) in 5th decade, 41 cases (28.9%) in 6th decade. 3. Chief complaint was hoarseness 127 cases (89.4 %), dysphagia 7 cases (4.9%) and sore throat, dyspnea etc. The time lag from the onset of hoarseness to the hospital was 2∼6 Months, 56 cases (44.0%), 6 Months∼l yrs, 34 cases (24%), within 2 Months, 17 cases (13.4%) and 15 cases (11.8%) were over 3yrs. Average time lag was 8.1 Months. 4. The site of laryngeal biopsy was 76 cases (53.3 %) from ture vocal cord, 23 cases (16.2%) from false vocal cord, and 19 cases (13.3%) from epiglottis. 5. Biopsy result was carcinoma in 69 cases (48.6%), laryngeal nodule in 20 cases (14.0%), laryngeal tuberculosis in 12 cases (8.4%) and non specific inflamation in 7 cases (5.0%). 6. 13.4% of the clinically impressed laryngeal carcinoma proved to be laryngeal tuberculosis, nonspecific inflammation etc.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.54 no.4
• /
• pp.105-114
• /
• 2012

Soil moisture plays a pivotal role in hydrological processes, especially in the forest which covers more than 64% of the national land. Soil moisture was monitored to analyze soil moisture change characteristics in terms of time and soil layers in this study. 2 Years soil moisture change data was obtained from the experimental nut pine forest and statistical analysis including auto-correlation and cross-corelation among soil moisture data from different soil layers was conducted. Using the monitored soil moisture data, a relationship between soil moisture change and precipitation was analyzed and seasonal soil moisture change characteristics were analyzed. From the result of inter-relationships among soil layers in terms of season and time lag, soil moisture change characteristics in the nut pine forest were upper soil layers were much sensitive than lowers, and seasonal variation if soil moisture for upper soil layers were bigger than lowers showing low correlation with precipitation in winter and spring due to freezing and snowfalls.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2017.05a
• /
• pp.193-193
• /
• 2017

Trend analysis can enhance our knowledge of the dominant processes in the area and contribute to the analysis of future climate projections. The results of previous studies in South Korea showed that southeast regions of Korea had the highest value of evapotranspiration. Thereby, it is of interest to determine the trend analysis in hydrological variables in this area. In this study, the recent 35 year trends of precipitation, reference evapotranspiration, and aridity index in monthly and annual time scale will be analyzed over three stations (Pohang, Daegu, and Pusan) of southeast Korea. After removing the significant Lag-1 serial correlation effect by pre-whitening, non-parametric statistical Mann-Kendall test was used to detect the trends. Also, the slope of trend of the Mann-Kendall test was determined by using Theil-Sen's estimator. The results of the trend analysis of reference evapotranspiration on the annual scale showed the increasing trend for the three mentioned stations, with significant increasing trend for Pusan station. The results obtained from this research can guide development if water management practices and cropping systems in the area that rely on this weather stations. The approaches use and the models fitted in this study can serve as a demonstration of how a time series trend can be analyzed.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.287-287
• /
• 2020

2016년말 우리나라의 지하수 관측망은 국가지하수관측망, 지역지하수관측망, 수질전용측정망, 해수침투 관측망 등 다양한 목적하에 약 5,790개가 운영되고 있으며, 평균적으로 약 10년 정도의 관측 기간을 보유하고 있다. 이들 중에서 일 1회 이상 자동관측이 이루어지는 679개를 대상으로 지하수위 시계열자료의 특성을 분석하였다. ARIMA 분석 결과, AR(p) 모델은 전체의 56.8%인 386개, MA(q) 모델은 90.7%인 616개, Integration(d) 모델은 96.5%인 655개로 나타났다. AR(p) 모델중 가장 많은 경우를 보인 것은 AR(1), AR(2), AR(3) 등의 순이며, MA(q) 모델중 가장 많은 경우를 보인 것은 MA(2), MA(1), MA(3) 등의 순이며, Integration(d) 모델은 I(1), I(2)의 순으로 나타났다. AR(1) 모델이 가장 많은 것은 강우에 대한 지하수위의 교차상관의 lag time이 1 ~ 2일인 경우가 가장 많으므로 이전 시점의 지하수위에 의하여 현재 지하수위가 결정된다는 점을 의미한다. Integration이 많이 나타난 이유는 주기적 또는 지속적인 변동성이 지하수위에 나타나고 있음을 보여준다. 지하수위의 시계열 특성의 분류 및 그 원인을 평가하여 각 관측소별 지하수위 변동성을 정의함으로써 추후 지하수위 시계열자료의 분석 목적에 부합하는 자료 선별에 기여하고자 한다.

• Journal of Environmental Health Sciences
• /
• v.49 no.3
• /
• pp.149-158
• /
• 2023

Background: Injury is one of the major health problems in South Korea. Few studies have evaluated both intentional and unintentional injury when investigating the association between exposure to air pollutants and injury. Objectives: We aimed to explore the association between short-term exposure to ambient air pollution and years of life lost (YLLs) due to injury. Methods: Data on daily YLLs for 2002~2019 were obtained from the the Death Statistics Database of the Korean National Statistical Office. This study estimated short-term exposure to particulate matter with an aerodynamic diameter of <10 ㎛ (PM₁₀), particulate matter with an aerodynamic diameter of <2.5 ㎛ (PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃). This time series study was conducted using a generalized additive model (GAM) assuming a Gaussian distribution. We also evaluated a delayed effect of ambient air pollution by constructing a lag structure up to seven days. The best-fitting lag was selected based on smallest generalized cross validation (GCV) value. To explore effect modification by intentionality of injury (i.e., intentional injury [self-harm, assault] and unintentional injury), we conducted stratified subgroup analyses. Additionally, we stratified unintentional injury by mechanism (traffic accident, fall, etc.). Results: During the study period, the average daily YLLs due to injury was 307.5 years. In the intentional injury, YLLs due to self-harm and assault showed positive association with air pollutants. In the unintentional injury, YLLs due to fall, electric current, fire and poisoning showed positive association with air pollutants, whereas YLLs due to traffic accident, mechanical force and drowning/submersion showed negative associations with air pollutants. Conclusions: Injury is recognized as preventable, and effective strategies to create a safe society are important. Therefore, we need to establish strategies to prevent injury and consider air pollutants in this regard.