Among the information technology and automation that have rapidly developed in the manufacturing industries recently, tens of thousands of quality variables are estimated and categorized in database every day. The former existing statistical methods, or variable selection and interpretation by experts, place limits on proper judgment. Accordingly, various data mining methods, including decision tree analysis, have been developed in recent years. Cart and C5.0 are representative algorithms for decision tree analysis, but these algorithms have limits in defining the tolerance of continuous explanatory variables. Also, target variables are restricted by the information that indicates only the quality of the products like the rate of defective products. Therefore it is essential to develop an algorithm that improves upon Cart and C5.0 and allows access to new quality information such as loss cost. In this study, a new algorithm was developed not only to find the major variables which minimize the target variable, loss cost, but also to overcome the limits of Cart and C5.0. The new algorithm is one that defines tolerance of variables systematically by adopting 3 categories of the continuous explanatory variables. The characteristics of larger-the-better was presumed in the environment of programming R to compare the performance among the new algorithm and existing ones, and 10 simulations were performed with 1,000 data sets for each variable. The performance of the new algorithm was verified through a mean test of loss cost. As a result of the verification show, the new algorithm found that the tolerance of continuous explanatory variables lowered loss cost more than existing ones in the larger is better characteristics. In a conclusion, the new algorithm could be used to find the tolerance of continuous explanatory variables to minimize the loss in the process taking into account the loss cost of the products.1)
In the manufacturing industry fields, thousands of quality characteristics are measured in a day because the systems of process have been automated through the development of computer and improvement of techniques. Also, the process has been monitored in database in real time. Particularly, the data in the design step of the process have contributed to the product that customers have required through getting useful information from the data and reflecting them to the design of product. In this study, first, characteristics and variables affecting to them in the data of the design step of the process were analyzed by decision tree to find out the relation between explanatory and target variables. Second, the tolerance of continuous variables influencing on the target variable primarily was shown by the application of algorithm of decision tree, C4.5. Finally, the target variable, loss, was calculated by a loss function of Taguchi and analyzed. In this paper, the general method that the value of continuous explanatory variables has been used intactly not to be transformed to the discrete value and new method that the value of continuous explanatory variables was divided into 3 categories were compared. As a result, first, the tolerance obtained from the new method was more effective in decreasing the target variable, loss, than general method. In addition, the tolerance levels for the continuous explanatory variables to be chosen of the major variables were calculated. In further research, a systematic method using decision tree of data mining needs to be developed in order to categorize continuous variables under various scenarios of loss function.
Many enterprises have been adopting management systems good enough for them and operating the schemes to have competitive edge better than their competitor. One of the finest systems that most companies have been selecting is ISO 14001. ISO 14001, environment management system, is widely known as advancing internal efficiency and productivity in the various industries. As a result, the number of companies that have adopted ISO 14001’s certification have been increasing continuously year by year since ISO 14000 standard was called in 1994s from ISO 18000 standard that originally used. The purpose of this study is to present that ISO 14001’s requirement execution influences on management performance in the small manufacturer. In order to carry out this research, we obtained 96 survey sheets and inspected ten assumptions based on the reliability, validity of the questionnaires. The results of regression analysis are summarized as follows; First, the three factors of ISO 14001 requirement, plan, implementation and operation and management consideration, have an important effect on the operational performance. Second, the three elements of ISO 14001 requirement, environment policy, implementation and operation and management consideration, affect to the financial performance significantly. Based on the results, it is sure that the companies that execute the factors of implementation and operation and management policy have a good performance to achieve operational and financial performance so that it is important to clarify the member’s role, authority and follow the procedure by a company’s process. Also, the truth shows CEO’s continuous will and periodical review of ISO 14001 influence on management performance as well.
ISO 9001, quality management system, is widely known as advancing internal efficiency and productivity in various industry. As a result, the number of companies that have adopted ISO 9001’s certification have been increasing continuously year by year since ISO 9000’ family standard was published in 1987s. This fact shows that a lot of businesses are trying to get the accreditation for improving the competitiveness of quality. The purpose of this study is to present that ISO 9001’s certification motives affect to the requirement’s implementation and show that the execution of requirements influences on management performance in the small manufacturer. In order to carry out this research, we obtained 96 survey sheets and inspected twenty assumptions based on the reliability, validity of the questionnaires. The results of regression analysis are summarized as follows; First, the factors of certification motive influence on the requirement’s implementation except resources management. Second, the two elements of ISO 9001 requirement, resources management and product realization, have an important effect on the operational performance and financial performance considerably in the companies that choose the internal motive. Finally, the two requisites of ISO 9001 requirement, resources management and measurement, analysis and improvement, affect to the operational performance and financial performance significantly in the businesses that select the external motive. Based on the results, the companies that choose the internal motive have a good performance to execute the ISO 9001 requirements. Also, to implement the requirements of ISO 9001 is helpful for the companies to produce the operational and financial performance.
The purpose of this study is to present that the entrepreneurial orientation affects to management performance in the small manufacturer. In order to carry out this research, we obtained 171 survey sheets and inspected seven assumptions based on the reliability, validity of the questionnaires. The results of regression analysis are summarized as follows; First, the factor of entrepreneurial orientation, innovative-ness, influences on the technical innovation performance and financial performance significantly. Second, the element of entrepreneurial orientation, proactive-ness, has an important effect on the technical innovation performance and financial performance. Finally, the requisite of entrepreneurial orientation, risk taking, affects to the technical innovation performance significantly, but not the financial performance. Based on the results, the companies that achieve the technical innovation and financial performance have an atmosphere to encourage to perform the research and development works and find out innovative ideas and improvement points in processes. However, the entrepreneur is required to take careful judgement for determining the uncertain circumstance.
The purpose of this study is to introduce a empirical study of using Taguchi Method for the Entrepreneurial Orientation and Financial Performance. In this study, three factors of Entrepreneurial Orientation, innovation, pro-activity and risk taking, are used of the control factors and an element, period of establishment, is chosen as a noise factor. In order to carry out this research, we obtained 200 survey sheets and performed the reliability and validity analysis of the questionnaires and then the experiment was conducted by Taguchi's experimental design. To improve Financial Performance under the noise factor of period of establishment, optimal condition are as follows; the two factors of Entrepreneurial Orientation, innovation, pro-activity should be maintained to a high level. Also, other factor, risk taking should be performed as the level that the company has maintained. Through this paper, we find out that Taguchi method is applicable for analysis of questionnaire.
Multivariate control charts are widely needed to monitor the production processes in various industry. Among the several multivariate control charts, control chart have been used of the typical technique. The control chart shows a statistic that represents observed variables and monitors the process through the statistic. In this case, the statistic generally have the limit that any variables affect to that statistic. To solve this problem, some studies have been progressed in the meantime. The representative method is to disassemble total statistic into each of the variable value and make a decision the parameters with large values than threshold value as a main cause. However, the means is requested to follow the normal distribution. To settle this problem, the bootstrap technique that don't be needed the probability distribution was introduced in 2011. In this paper, I introduced the detection technique of the fault variables using multiple regression analysis. There are two advantages; First, it is possible to use less samples than the ascertainment technique applying to bootstrap. Second, the technique using the regression analysis is easy to apply to the actual environment because the global threshold value is used.
This study was carried out to study the survival rate of thawed Hanwoo embryos frozen by the slow-rate freezing or the cryotop vitrification method. Hanwoo cumulus-oocyte complexes were recovered from ovaries at a slaughter house, matured for 20~22 hours, fertilized with Hanwoo semen for 5~6 hours, and cultured for 7~9 days in 38.5℃, 5% CO2 incubator. For freezing, Day 7∼9 blastocysts were collected. Embryos for the slow-rate freezing were equilibrated in 1.8 M ethylene glycol (EG) with Dulbecco's phosphate-buffered saline (D-PBS). Programmable cell freezer was precooled down to —7℃, and the straw was seeded during 8 minutes-holding time, and was cooled to —35℃ at the cooling rate of 0.3℃/min, and then was plunged and stored in liquid nitrogen. Embryos for the cryotop vitrification were treated in TCM199 with 0.5 M sucrose, 16% EG, 16% dimethylsulfoxide (DMSO). Embryos were then loaded individually onto cryotop and plunged directly into liquid nitrogen. The survival rates of embryos frozen by these two freezing methods were evaluated at 12 to 24h post-thawing. The survival rates of frozen/thawed Hanwoo embryos by the cryotop vitrification method (56.86 ± 26.53%) were slightly higher than those by the slow-rate freezing method (55.07 ± 26.43%) with no significant difference. Using the cryotop vitrification and the slow-rate freezing of Hanwoo blastocysts on Day 7 following in-vitro fertilization (IVF) treatment, the survival rates of frozen/thawed Hanwoo embryos were 72.65 ± 18.3% and 79.06 ± 17.8%, respectively. The survival rates by the cryotop vitrification were higher than those by the slow-rate freezing on both Day 8 and 9 with significantly higher survival rate on Day 9 (p<0.05). Using the cryotop vitrification and the slow-rate freezing of Hanwoo embryos to compare between three different blastocyst stages, the survival rates of the blastocyst stage embryos were 66.22 ± 18.8% and 45.76 ± 12.8%, respectively with higher survival rate by the vitrification method (p<0.05). And the survival rate of expanded blastocysts was higher than those of early blastocysts and blastocysts in two freezing methods with significantly higher
survival rate by the slow-rate freezing method (p<0.05).
We investigated the effects of heavy metals in cement in the last 3 years and the amount of waste in the cement manufacturing process. The result shows that the average Cr6+ content in cement products is controlled at 10 mg/kg. Cu and Pb have lower detection tendency in white cement than in ordinary portland cement. In addition, heavy metals such as Cd show a certain level of detection regardless of the input wastes. Copper slag and phosphate gypsum are the main influencing factors on the heavy metals in cement products. In auxiliary fuels, plastics waste and wood waste are considered to affect heavy metals in cement products. Alternative raw materials are considered to be affected by the alternative raw materials managed as byproducts. In the case of supplementary fuels, auxiliary fuels managed as waste instead of auxiliary fuels managed as byproducts affect the heavy metals in cement. This study examined the input amount without considering the heavy metals in each waste. Therefore, the result may vary in different situations, and further research must be conducted to supplement the findings. However, if the heavy-metal contents in the waste are constant, it can be used as a reference material for the control of heavy metals in cement products.
Engineered nanomaterials (ENMs) can be released to humans and the environment through the generation of waste containing engineered nanomaterials (WCNMs) and the use and disposal of nano-products. Nanoparticles can also be introduced intentionally or unintentionally into waste streams. This study examined WCNMs in domestic industries, and target nanomaterials, such as silicon dioxide, titanium oxide, zinc oxide, nano silver, and carbon nanotubes (CNTs), were selected. We tested 48 samples, such as dust, sludge, ash, and by-products from manufacturing facilities and waste treatment facilities. We analyzed leaching and content concentrations for heavy metals and hazardous constituents of the waste. Chemical compositions were also measured by XRD and XRF, and the unique properties of nano-waste were identified by using a particle size distribution analyzer and TEM. The dust and sludge generated from manufacturing facilities and the use of nanomaterials showed higher concentrations of metals such as lead, arsenic, chromium, barium, and zinc. Oiled cloths from facilities using nano silver revealed high concentrations of copper, and the leaching concentrations of copper and lead in fly ash were higher than those in bottom ash. In XRF measurements at the facilities, we detected compounds such as silicon dioxide, sulfur trioxide, calcium oxide, titanium dioxide, and zinc oxide. We found several chemicals such as calcium oxide and silicon dioxide in the bottom ash of waste incinerators.
This study investigated the concentration of heavy metals in blast-furnace slag cement by changing the content ratio between blast-furnace slag and ordinary Portland cement for the safe recycling of blast-furnace slag in the cement industry. The analysis of the three main materials of the cement (ordinary Portland cement, blast-furnace slag, and the alternative raw materials), resulted in the ordinary Portland cement having the highest concentration of heavy metals. Also, it is concluded that the heavy metal content of blast-furnace slag cement is mainly attributed to the content of ordinary Portland cement. As the content of furnace slag during the manufacture of cement increases, the overall heavy metal content of the furnace slag cement becomes low. This was highly evaluated as a resource in the cement-production process, in respect of the effective recycling of resources and the safe management of hazardous materials.
폐기물의 국가 간 이동 시 선진국 등 자국의 폐기물에 대한 엄격한 규제를 피하기 위해서 부적정 처리를 진행해 왔으며 이러한 이슈는 국제문제로 대두되었다. 특히 1976년 이탈리아 소베소에서 발생한 다이옥신 유출사고 때 증발한 폐기물이 1983년 그린피스에 의해 프랑스의 한 마을에서 발견되었고, 그 후 1987년 6월 ‘유해폐기물의 환경적이고 건전한 관리를 위한 타이로 지침과 원칙’이 채택된 카이로 지침을 바탕으로 1989년 3월 스위스 바젤에서 세계 116개국 대표가 참석한 가운데 바젤협약(1992년 5월 협약 발효)이 채택되었다. 이에 따라 우리나라는 1994년 바젤협약에 가입함에 따라 폐기물국가간이동법을 제정하여 수출입 폐기물을 바젤협약의 분류체계로 전환하였으며, 최근에는 수출입 규제폐기물과 관리폐기물로 구분하여 관리하고 있다. 최근 들어 바젤협약 당사국총회에서는 국가 간 수출입 폐기물 규제와 효율적인 관리를 위한 제도마련을 회원국들에 요구하고 있으며, 우리나라(환경부 및 국립환경과학원)에서도 이에 맞추어 수입 및 수출되는 폐기물의 통관절차・이동・유통・저장 및 재활용 처리 등 전 부분에 걸쳐 관리체계의 개선에 대해 효과적인 방안을 모색하고 있다. 그럼에도 불구하고 규제 및 관리폐기물 판단기준 부제, 폐기물과 중고제품 구분의 모호성, 수출입 폐기물 품목 세부 분류의 필요성 등 많은 문제점이 나타나고 있는 것도 사실이다. 이에 대해 본 연구에서는 수출입 폐기물 관리체계 개선을 위한 문제점과 이를 극복할 앞으로의 해결 방안에 대해 언급하고자 하였다.
수은의 전과정 관리를 통한 환경배출 저감을 위한 미나마타 협약이 2017년 8월에 발효되면서 비준 절차를 진행하고 있는 우리나라 또한 수은을 함유한 제품 또는 폐기물을 친환경적으로 보관 및 폐기해야 한다. 우리나라는 의도적 사용을 위해 원소상 수은을 수입해 왔으나, 수은첨가제품 및 정광 불순물 등 비의도적으로 수은이 유입되어 왔다. 이렇게 비의도적으로 유입된 수은의 69%가 고농도 수은함유폐기물의 형태로 지정폐기물로 구분되어 지정폐기물 유입시설로 유입되고 있는 것으로 추정되고 있다. 그러나 수은함유 폐기물 매립시설 주변대기 중 수은 농도가 우려됨에 따라 수은함유 폐기물의 친환경적인 매립 관리기준과 함께 고수은함유폐기물의 회수 및 처리에 대한 관심이 높아지고 있다. 특히 수은은 대기로의 휘발량이 큰 금속으로 알려져 있으며, 수은함유 폐기물 매립지에서 원소상 수은의 형태로 전환되어 환경 중으로 재유입될 가능성이 있다. 국외의 경우 고농도 수은함유 폐기물의 회수 및 처리에 대한 기준을 두고 있으나 국내에서는 아직 수은 회수에 대한 법적 근거가 마련되어 있지 않은 상황이다. 본 연구에서는 국내 업체에서 발생하고 있는 고농도 수은함유폐기물(비철금속 발생 슬러지)을 대상으로 시간별 온도별에 따른 대상 폐기물 내 수은 함유량 및 용출량 실측을 통해 고농도 수은함유 슬러지 중 최대 비산율 및 온도별 속도상수를 구하고자 하였다. 이를 통해 고농도 수은함유 폐기물의 환경 중 수은 배출 저감 방향을 제시함으로 향후 수은함유 폐기물의 적정 관리기준 설정에 기초자료로 활용될 것으로 판단된다.
Waste lead-acid batteries accounted for 83% (470,000 tons) of the licensed waste imported into the country in 2015, which was the largest percentage of imported waste in Korea. In addition, there is the problem of negligent management or waste circulation related to international conventions. Therefore, it is necessary to grasp the current status of domestic recycling management and the management of waste batteries. In this study, the current status of domestic and foreign management of waste lead-acid batteries, which is the largest component of imported waste, was investigated. In addition, we examined the import/export regulations, inadequate management or distribution of waste related to international treaties such as the Basel Convention and the Organization for Economic Co-operation and Development (OECD) regulations, and the problem of appropriate treatment management, especially considering waste lead-acid batteries. We studied the proper management method and system for waste lead-acid batteries treatment in Korea, and investigated and compared domestic and foreign laws and treatment guidelines for domestic waste, including those for imported and exported waste. We established a safe resource waste-recycling management system to help the utilization of the basic data necessary for waste management law and business support in relation to international treaties.
The purpose of this study is to understand the current situation for waste generation from domestic industries and to calculate the designated waste generation containing heavy metals using Korean waste statistics. Analytical data regarding heavy metals for hazardous waste in a previous study was reviewed. In addition, the designated waste generation for each heavy metal was estimated by comparing the data of the Allbaro system (2014). The designated waste generations were, in order, Pb > CN−> Cd > Cu > Hg > Cr6+ > As, and the sludge, ash, slag, dust, etc. generated from the process of wastewater treatment, plating and anodizing of metals, waste treatment, and the manufacture of basic iron and steel, considered as designated waste containing heavy metals, were investigated. The waste generation with heavy metals was 1.812 % of the total waste generation, which is higher than the 1.317 % collected from the Allbaro system (2014). These results will be used as a baseline in establishing waste management policy. Further analytical data about heavy metals in the designated wastes that are mentioned in this study are required for a more accurate picture of waste generation containing heavy metals.
By the end of 2012, the recycled proportion of domestic waste tires was 287,330 ton (93.9%) of the amount of waste tires discharged (305,877 ton). The waste tires have been reused for heat supply, material recycling and other purposes; the proportions are 50.1%, 20.7% and 23.1%, respectively. In the case of heat supply, waste tires are supplied to cement kiln (104,105 ton, 68%), RDF manufacture facilities (47,530 ton, 31%) and incinerators (1,923 ton, 1%). Recently, there has been an increase in the use of waste tires at power generation facilities as an auxiliary fuel. Thus, physico-chemical analysis, such as proximate analysis, elemental analysis and calorific value analysis have been carried out to evaluate potential of waste tires as an auxiliary fuel in Korea. The LHV (Lower Heating Value) of waste tires is approximately 20% higher than that of coal, at an average of 8,489 kcal/kg (7,684 ~ 10,040 kcal/kg). Meanwhile, the sulfur content is approximately 1.5wt. %, and balance of plant (e.g. pipe line, boiler tube, etc.) may be corroded by the sulfur. However, this can be prevented by construction and supplementation with refractories. In this study, TDF (Tire Derived Fuel) produced from waste tires was co-combusted with coal, and applied to the CFB (Circulating Fluidized Bed) boiler, a commercial plant of 100 tons/day in Korea. It was combined with coal, ranging from 0 to 20wt. %. In order to determine the effect on human health and the environment, gas emission such as dioxin, NOx, SOx and so on, were continuously analyzed and monitored as well as the oxygen and carbon monoxide levels to check operational issues.
시멘트 산업에서는 폐자원의 재활용과 비용절감 및 생산 효율성을 증가시키기 위하여 고로슬래그, 석탄재, 폐수처리오니, 폐타이어, 폐합성수지 등 다양한 폐기물이 보조연료 및 대체원료로 사용되고 있다. 그러나 이로 인하여 시멘트 제품의 유해성, 주변 환경 영향 등에 대한 논란을 유발하고 있다. 이에 따라 시멘트 제품의 품질의 안전성과 환경 유해성에 대한 사회적 논란을 해소하기 위해서 시멘트 중 육가크롬을 20 mg/kg으로 관리 중이며, 육가크롬을 포함하여 6개 중금속(Cr6+, As, Cu, Cd, Pb, Hg)에 대하여 매월 모니터링 중이다. 모니터링에 분석되는 시멘트는 보통 포틀랜드 시멘트를 대상으로 함에 따라 다른 종류의 시멘트에 대한 중금속 함유량을 파악할 필요성이 있다. 따라서 본 연구에서는 고로슬래그를 이용한 고로슬래그 시멘트에 대한 중금속 함유특성을 파악하고자 하였다. 그 결과 고로슬래그 시멘트의 경우 대부분 고로슬래그와 보통 포틀랜드 시멘트가 50 % : 50 %로 혼합하여 생산되고 있었으며, 고로슬래그가 혼합됨에 따라 중금속 함유량이 낮아지는 것을 파악하였다. 또한, 공사현장에서 초기 강도가 낮은 단점이 있으나 자원 재활용 및 유해물질 안전관리 측면에서 볼 때 고로슬래그 시멘트의 사용은 부가가치 및 환경성이 높다고 평가된다.
In South Korea, the “Waste Control Act” regulates the use and purpose of recycling waste and specifies recycling methods and specific standards. However, these processes requires a long time and large budget, because they need to be reviewed based on data specific to the type of waste involved. The use and purpose of recycling can be considered by its functional and environmental aspects. The functional aspect of recycling may vary widely, depending on product characteristics In contrast, environmental standards will have more points in common. Recycling standards that consider the environmental impact and characteristics of waste are not prepared specifically. Therefore, when a large amount of waste is recycled, or recycling standards are applied to a new type of waste, the methodology for review of its environmental characteristics can be controversial. This study is meant to recognize the necessity of recycling standards and to prepare environmental standards and new recycling purposes for waste related to recycling three types of gypsum waste (phospho, titan, desulfurization). Several companies were selected for this study. In the gypsum waste-generating company, gypsum waste samples were collected and analyzed for pH, heavy metal content, water content, hazardous substance content, etc. In addition, we attempted to obtain the company's opinions on waste recycling. We determined the hazardous materials found in these three types of gypsum waste, raised awareness of waste, and confirmed that industry waste can be efficiently recycled for new uses under the improved.
In South Korea, as the price of natural minerals and lack of domestic resources increases, the import of waste into certain countries is gradually increasing. The largest portion of waste subject to a domestic import permit are lead-acid batteries. They account for more than 90% of the total import permits. In this study, the current status of waste leadacid batteries imported into Korea and their recycling status at domestic battery recycling sites were investigated. Waste generated from various lead-acid battery recycling plants were investigated for effective management of these batteries in South Korea. In addition, hazardous substances in the waste generated at recycling sites were analyzed to determine their environmental risk. Study sources were selected based on the industries registered on the Allbaro-system. For leaching analysis results, an arsenic content of 30.4 mg/L (1.63 to 109.13) was detected in slag, and 0.018 mg/L (N.D. to 0.018) of mercury was detected in wastewater treatment sludge. The contents of lead in slag and wastewater-treated sludge were measured as 85,599 mg/kg (52,476.4 to 150,466.8) and 41,722 mg/kg (18,082.6 to 68,958.1), respectively. In battery case scrap that was recycled by a second recycling company, lead was found to be 5.79 mg/L, exceeding the designated waste criteria of 3 mg/L. However, after the washing process, lead was no longer detected in the recycled product, P2. We conclude that it is necessary to keep the current secondary recycling process, with recycling after the cleaning process, in order to allow primary recycling companies to appropriately manage designated waste as it is discharged, collected, and transported.
In this study, we analyzed the content of five hazardous heavy metals (Pb, As, Hg, Cd, and Cu) in cement products distributed in Korea over the last five years. The types and amounts of waste inputted into a cement kiln or added as alternative fuels and secondary raw materials were investigated, and the correlation between heavy metal content and input waste were analyzed. The measured heavy metal content in cement products were 26.9-95.0 mg/kg for lead, 6.08-19.15 mg/kg for arsenic, 0.0339-0.2617 mg/kg for mercury, 2.937-4.392 mg/kg for cadmium, and 22.25-267.42 mg/kg for copper. In addition, based on correlation analysis results between the heavy metal content of cement products and added input wastes, major wastes that affected the heavy metal content among the 11 types of waste were iron, coal ash, waste tires, waste plaster, desulfurization gypsum, and waste synthetic resin.