Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: Sung-Min Park x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

This paper is an investigation of the knowledge sources of Korean innovation studies using citation analysis, based on a Korean database during 1993–2004. About two thirds of knowledge has come from foreign sources and 94% of them are from English materials. Research Policy is the most frequently cited journal followed by Harvard Business Review, R&D Management and American Economic Review. An analysis of who cites the most highly cited journal is also included. Neo-Schumpeterians in Korea cite more papers from Research Policy than general researchers, and there is no difference between groups in the year of citation.

Restricted access

Abstract  

Recovered salt can be reused in the electrorefining process and the final removed salt from uranium (U) deposits can be fed into a following U casting process to prepare ingot. Therefore, salt distillation process is very important to increase the throughput of the salt separation system due to the high U content of spent nuclear fuel and high salt fraction of U dendrites. Yields on salt recovered by a batch type vacuum distiller transfer device were processed for obtaining pure eutectic salt and U. In this study, the influence of the various temperature slopes of each zones on salt evaporation and recovery rate are discussed. From the experimental results, the optimal temperature of each zones appear at the Top Zone and Zone 1 is 850 °C, Zone 2 is 650 °C and Zone 3 is 600 °C, respectively. In these conditions, the complete evaporation of pure salt in 1.4 h occurred and the amount of recovered salt was about 99 wt%. The adhered salt in U deposits was separated by a temperature slope zone of salt distillation equipment. From the experimental results using U deposits, the amount of salt evaporation was achieved more than 99 wt% and the salt evaporation rate was about 1.16 g/min. Also, the mount of recovered salt was about 99.5 wt%.

Restricted access

Abstract

Platinum catalysts supported on silicas with various physicochemical properties were prepared in order to investigate the effect of silica characteristics on their platinum dispersion and catalytic activity in the oxidation of carbon monoxide. Although titania-incorporation into silica and further treatment of the impregnated platinum precursor with hydrogen peroxide were effective for improving the dispersion and stability of platinum catalysts supported on silicas, regardless of the characteristic of the silicas, the platinum catalysts supported on fumed silica with a medium level of surface hydroxyl group concentration exhibited the highest catalytic activity among those supported on mesoporous silica, silica gel, and precipitated silica. The required properties of the highly active platinum catalyst seemed to be a high dispersion of platinum, the formation of a stable titania layer, and the generation of strong acid sites. By contrast, the precipitated silica with a small surface area and high concentration of surface hydroxyl groups was not appropriate for a catalytic support for platinum catalysts.

Restricted access

Abstract

Background and aims

Problem gambling among adolescents has recently attracted attention because of easy access to gambling in online environments and its serious effects on adolescent lives. We proposed a machine learning-based analysis method for predicting the degree of problem gambling.

Methods

Of the 17,520 respondents in the 2018 National Survey on Youth Gambling Problems dataset (collected by the Korea Center on Gambling Problems), 5,045 students who had gambled in the past 3 months were included in this study. The Gambling Problem Severity Scale was used to provide the binary label information. After the random forest-based feature selection method, we trained four models: random forest (RF), support vector machine (SVM), extra trees (ETs), and ridge regression.

Results

The online gambling behavior in the past 3 months, experience of winning money or goods, and gambling of personal relationship were three factors exhibiting the high feature importance. All four models demonstrated an area under the curve (AUC) of >0.7; ET showed the highest AUC (0.755), RF demonstrated the highest accuracy (71.8%), and SVM showed the highest F1 score (0.507) on a testing set.

Discussion

The results indicate that machine learning models can convey meaningful information to support predictions regarding the degree of problem gambling.

Conclusion

Machine learning models trained using important features showed moderate accuracy in a large-scale Korean adolescent dataset. These findings suggest that the method will help screen adolescents at risk of problem gambling. We believe that expandable machine learning-based approaches will become more powerful as more datasets are collected.

Open access
Journal of Radioanalytical and Nuclear Chemistry
Authors:
Yong-Sam Chung
,
Sun-Ha Kim
,
Jong-Hwa Moon
,
Sung-Yeol Baek
,
Young-Jin Kim
,
Hark-Rho Kim
,
Il-Jin Park
, and
Kyung-Sik Min

Abstract  

A fast pneumatic transfer system for an instrumental neutron activation analysis and delayed neutron counting system were reconstructed with new designs of a functional improvement at the HANARO research reactor in 2006. The design, conception, operation and control of these systems are described. Also the experimental characteristic parameters by a functional operation test and an irradiation test of these systems, such as the transfer time, the neutron flux, the temperature of the irradiation position with an irradiation time, the radiation dose rate when the rabbit is returned, etc., are reported to provide a user information as well as for the management and safety of the reactor.

Restricted access