• Title/Summary/Keyword: PROCESS VARIABLES

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Supercritical Water Oxidation of Anionic Exchange Resin (초임계수 산화를 이용한 음이온교환수지 분해)

  • Han, Joo-Hee;Han, Kee-Do;Do, Seung-Hoe;Kim, Kyeong-Sook;Son, Soon-Hwan
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.5
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    • pp.549-557
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    • 2006
  • The characteristics of supercritical water oxidation have been studied to decompose the waste anionic exchange resins which were produced from a power plant. The waste resins from a power plant were mixture of anionic and cationic exchange resins. The waste anionic exchange resins had been separated from the waste resins using a solid-liquid fluidized bed. It was confirmed that the cationic exchange resins were not included in the separated anionic exchange resins by the elemental and thermogravimetric analysis. A slurry of anionic exchange resins which could be fed continuously to a supercritical water oxidation apparatus by a high pressure pump was prepared using a wet ball mill. Although the COD of liquid effluent had been reduced more than 99.9% at 25.0 MPa and $500^{\circ}C$ within 2 min, the total nitrogen content was reduced only 41%. The addition of nitric acid to the slurry could reduce the total nitrogen content in treated water. The central composite design as a statistical desist of experiments had been applied to optimize the conditions of decomposing anionic resin slurry by means of the COD and total nitrogen contents in treated waters as the key process output variables. The COD values of treated waters had been reduced sufficiently to $99.9{\sim}100%$ af the reaction conditions of $500{\sim}540^{\circ}C$, 25.0 MPa within 2 min. The effects of temperature and nitric acid concentration on COD were not significant. However, the effect of nitric acid concentration on the total nitrogen was found to be significant. The regression equation for the total nitrogen had been obtained with nitric acid concentration and the coefficient of determination($r^2$) was 95.8%.

Predicting the Performance of Recommender Systems through Social Network Analysis and Artificial Neural Network (사회연결망분석과 인공신경망을 이용한 추천시스템 성능 예측)

  • Cho, Yoon-Ho;Kim, In-Hwan
    • Journal of Intelligence and Information Systems
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    • v.16 no.4
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    • pp.159-172
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    • 2010
  • The recommender system is one of the possible solutions to assist customers in finding the items they would like to purchase. To date, a variety of recommendation techniques have been developed. One of the most successful recommendation techniques is Collaborative Filtering (CF) that has been used in a number of different applications such as recommending Web pages, movies, music, articles and products. CF identifies customers whose tastes are similar to those of a given customer, and recommends items those customers have liked in the past. Numerous CF algorithms have been developed to increase the performance of recommender systems. Broadly, there are memory-based CF algorithms, model-based CF algorithms, and hybrid CF algorithms which combine CF with content-based techniques or other recommender systems. While many researchers have focused their efforts in improving CF performance, the theoretical justification of CF algorithms is lacking. That is, we do not know many things about how CF is done. Furthermore, the relative performances of CF algorithms are known to be domain and data dependent. It is very time-consuming and expensive to implement and launce a CF recommender system, and also the system unsuited for the given domain provides customers with poor quality recommendations that make them easily annoyed. Therefore, predicting the performances of CF algorithms in advance is practically important and needed. In this study, we propose an efficient approach to predict the performance of CF. Social Network Analysis (SNA) and Artificial Neural Network (ANN) are applied to develop our prediction model. CF can be modeled as a social network in which customers are nodes and purchase relationships between customers are links. SNA facilitates an exploration of the topological properties of the network structure that are implicit in data for CF recommendations. An ANN model is developed through an analysis of network topology, such as network density, inclusiveness, clustering coefficient, network centralization, and Krackhardt's efficiency. While network density, expressed as a proportion of the maximum possible number of links, captures the density of the whole network, the clustering coefficient captures the degree to which the overall network contains localized pockets of dense connectivity. Inclusiveness refers to the number of nodes which are included within the various connected parts of the social network. Centralization reflects the extent to which connections are concentrated in a small number of nodes rather than distributed equally among all nodes. Krackhardt's efficiency characterizes how dense the social network is beyond that barely needed to keep the social group even indirectly connected to one another. We use these social network measures as input variables of the ANN model. As an output variable, we use the recommendation accuracy measured by F1-measure. In order to evaluate the effectiveness of the ANN model, sales transaction data from H department store, one of the well-known department stores in Korea, was used. Total 396 experimental samples were gathered, and we used 40%, 40%, and 20% of them, for training, test, and validation, respectively. The 5-fold cross validation was also conducted to enhance the reliability of our experiments. The input variable measuring process consists of following three steps; analysis of customer similarities, construction of a social network, and analysis of social network patterns. We used Net Miner 3 and UCINET 6.0 for SNA, and Clementine 11.1 for ANN modeling. The experiments reported that the ANN model has 92.61% estimated accuracy and 0.0049 RMSE. Thus, we can know that our prediction model helps decide whether CF is useful for a given application with certain data characteristics.

The Effect of the Degree of Competition of the Hospital Market Regions on Clinic's Rate of Antibiotics Prescription (병원시장지역 내 경쟁 정도가 의원급 의료기관의 항생제 처방률에 미치는 영향)

  • Jo, Changik;Lim, Jae-Young;Lee, Soo Yeon
    • KDI Journal of Economic Policy
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    • v.30 no.2
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    • pp.129-155
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    • 2008
  • The rate of antibiotics prescription for an acute airway infection significantly varies depending upon the diagnosis type, specialty, and the location of the hospital along with many other related factors. The objective of this study is to empirically investigate the possible relationship between the antibiotics prescription rates for an acute airway infection and the degree of competition in the hospital market regions of mainly the providers of primary medical care services such as clinics, internal medicines, pediatrics and otorhinolaryngology department. Using the data from Health Insurance Review and Assessment Service (HIRA) regarding the hospitals' antibiotics prescription rates for the acute airway infection and controlling for selected variables of demand and supply sectors, this study tries to figure out that the degree of competition in the hospital market, regardless of what type of competition indexes we employed, has a statistically significant effect on the variations of antibiotics prescription rate of the clinics in local areas. This result implies that as an economic consideration itself, the change in the degree of competition in the hospital market can play a crucial role influencing the treatment behaviors of the medical doctors. More specifically, this study reveals that as the degree of competition increases the antibiotics prescription rate goes up. This result means that if the market becomes more competitive in a specific region so that it might cause a reduction in doctor's income, doctors with rational decision-making process, recognize that the benefit created from inducing patients' seemingly unnecessary demand for medical care (income effect) would be higher than the costs associated with sustaining their targeted income (substitution effect). It is because that the doctors are more likely to prescribe antibiotics which create relatively higher margins than other medical care services in order to sustain their targeted income when the hospital market competition becomes tighter. Even though this study empirically confirms that antibiotics prescription can be affected by the economic incentives, it still raises following issues as limitations of the study: first issue is about the representativeness of the hospital regions segregated for this study, which might be weak in explaining whether these regions are mutually exclusive in reality. Patients actually consider the quality of services, transportation cost, time costs, and any other related factors choosing the doctors or hospitals, and in that sense, this study rules out 'border-crossing' in using the medical care services. Second issue arises in capturing the data of antibiotics prescription rate. Since we use the average rate for each medical institution, we cannot figure out the average rate for each patient so that we are not able to control for the variation of patients' medical conditions. It is because of the unavailability of data regarding each patient's medical condition from HIRA. Thirdly, since this study mainly analyzes the medical institutions providing primary care such as clinics, internal medicines, pediatrics, and otorhinolaryngology department, it is skeptical of whether those institutions can represent the hospital market in respective regions and truly reflect the degree of competition. It needs to extend the study areas and disease types as well as any micro data for future studies.

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The Effect of the Participative Leadership on Creative Behavior - Focusing on Unidimensional and Multidimensional Mediating Effects of Psychological Empowerment - (참여적 리더십이 창의적 행동에 미치는 영향 - 심리적 임파워먼트의 단일차원과 다차원 매개효과를 중심으로 -)

  • Tak, Je-Woon;Shin, Je-Goo
    • Management & Information Systems Review
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    • v.36 no.5
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    • pp.61-83
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    • 2017
  • The purpose of this study is to investigate the mediating effects of psychological empowerment between participative leadership and creative behavior. Especially, it aims to analyze the unidimension and multidimension of psychological empowerment in an integrated manner, and to suggest effective practice of participative leadership together with theoretical and methodological implications. In this study, the dependent variable was measured separately with time lag as a method to solve the common method bias that can be shown by the self-report type survey method, and positive emotions and negative emotions expressing emotional states in job situations were employed as control variables along with rank. A total of 283 questionnaires were collected from employees who work for companies in various industries with more than 300 domestic employees. SPSS PROCESS macro program('model 4') was used for statistical analysis. Results, First, the full mediation effect of psychological empowerment(unidimension) was confirmed in the relationship between participative leadership and creative behavior. Second, the analysis of the multidimension of psychological empowerment revealed the full mediating effect of meaning, self-determination, and impact, and the mediating effect of competence was not significant. Third, as a result of comparing the mediating effects of unidimension of psychological empowerment and the mediating effects of multidimension, the magnitude of mediating effect of unidimension was found to be much greater than mediating effect of multidimension. And The magnitudes of the three multidimensional mediating effects were similar. This is a case in which the motivational model of participative leadership revealed in the overseas study is proven in the domestic management environment and is significant in that it is the basis of future research. Based on the results of the empirical studies, the implications and limitations of the study and future research directions are presented.

Clinical Evaluation of Surgical Resection of Pulmonary Tuberculosis (폐결핵에 대한 외과적 치험)

  • Park, Seung-Kyu;Shon, Mal-Hyun;Han, Dong-Gi;Ha, Hyun-Chul;Jin, Young-Ho;Song, Sun-Dae
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.4
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    • pp.474-480
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    • 1995
  • Background: In spite of initial intensive and long-term chemotherapy for pulmonary tuberculosis, many problems remain in the treatment of the residual lesion. The role of surgical intervention for pulmonary tuberculosis is getting rid of such residual lesion of pulmonary tuberculosis to support the healing process and to induce bacteriologically negative conversion in the end. Method: We experienced 30 cases of pulmonary resection for pulmonary tuberculosis from Aug. 1994 through Apr. 1995 in National Masan Tuberculosis Hospital. We conducted retrospective study to analyze several variables for the cases. Results: 1) The ratio between male and female was 4:1(male 24, female 6) and the age of peak incidence was in 3rd and 4th decades. 2) Indications for pulmonary resection in the radiographic findings were cavitary lesions of 19 cases(63.3%), destroyed one side of 8 cases(26.7%) and destroyed one lobe of 3 cases(10%). 3) 16 of 20 cases with unilateral lesions and all of 10 cases with bilateral lesions on chest X-ray films showed AFB positive on preoperative sputum smears. 14 cases(87.5%) of unilateral lesions and 9 cases(90%) of bilateral ones were converted into AFB negative postoperatively. Negative conversion rates of pneumonectomy and lobectomy cases were 100% and 85.7%, respectively. 4) Preoperative combined disease was 3 cases(10%) of DM and postoperative complications were 2 cases(6.7%) of dead space and no death. Conclusion: Chemotherapy only has some limitation in treatment of all tuberculosis. So, surgical intervention for pulmonary tuberculosis is an effective method as partner of chemotherapy.

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Study on the Adolescent′s Attitude Patterns toward the Meaning of Aging and the Elderly - Q-Methodology - (노인의 의미에 관한 청소년의 태도 유형 연구 - Q 방법론 적용 -)

  • Park In Sook;Lee Keum Jae
    • Child Health Nursing Research
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    • v.5 no.3
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    • pp.292-304
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    • 1999
  • The lengthened average span of human life by virtue of recent developments in medicine has caused the Population of elders to increase. The development of modern industrial society has transformed family structure from the large family system to that of a nuclear family. Due to the shift in family structure, the problem of support for the aged has surfaced as a nursing problem as well as a social problem. With regard to this problem, this study aims to investigate the adolescent's understanding of elders and aging. By identifying their understanding and classifying their attitude patterns, this study will help the nursing assessment of the support of elders in the family. This study employed Q-methodology and the research was conducted from December 1998 to May 1999. One method of the research included deep interviews with elders, those who are in their 50's. 40's or 30's. and the adolescent. 183 Q-Populations taken from literary works such as poems or novels were also formed as another method. Finally. 36 Q-cards were made after consultation with Professors of the nursing department. The subjects of the P- sample were 30 high sohoolboys/girls - who were in first, second, and third years. The result showed that 3 factors provided an explanation for 59.14% of the whole variables: the first factor, 41.37%; the second factor. 11.49%, and the third factor. 6.28%. These three factors were analyzed and categorized as three types. Twenty subjects out of the 30 were included in Type 1: Respecting Elders. The statements which showed the most positive consent were as follows: 'The declining age is a perfect time to prosper completing a worthy life' ; 'Getting old. one needs financial stability' and 'Elders wish the best for their children' The statements showing the most negative response were as follows: 'It is better to die than to live as an older person' ; 'Elders are insignificant' ; and 'Getting old is the worst unhappiness that tortures human.' Four subjects were included in Type 2. Resenting Elders. The statements which showed the most positive consent were as follows: 'Aging is a process of dying that nobody can escape from'. 'Elders should be concerned about his health and try to maintain their health' ; and 'When you set older. you regret about the life in the Past.' The statements showing the most negative response were as follows: 'When You get older. You should stand aloof greed and worldly things' 'When You got older, You become generous and gentle' ; and 'When You set he gets old. You change to become a comfortable and warm person.' Six out of 30 subject were included in Type 3 Caring Elders. The statements which showed the most positive consent were as follows: 'Elders should be concerned about his health and try to maintain their health' ; 'Elders wish the best for their children' ; and 'Elders deserve to be treated with filial respects.' The statements showing the most negative response were as follows 'Elders are insignificant' ; 'Elders have freedom and plenty of free time.' and 'Elders are alienated form and drove out of the society.' The above-mentioned results show that most adolescents in Korea recognize aging as the time of fruition and development: it is a time of benefiting and giving back to society. Aging can also be seen as a time of generosity and magnanimity and the time of respect and favorable treatment from society. despite the change of modern society and the ostensible transformation of a family system. Their recognition seems deeply rooted in the traditional confucian values and the dual family system which is Peculiar especially to the Korea - one which maintains both the superficial form of nuclear family and the substantial mode of the enlarged family system. In sum, many Korean adolescents attribute the meaning of the elderly and aging to the type of the respect with the elderly and the type of the elderly's caretaking.

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A Funding Source Decision on Corporate Bond - Private Placements vs Public Bond - (기업의 회사채 조달방법 선택에 관한 연구 - 사모사채와 공모사채 발행을 중심으로 -)

  • An, Seung-Cheol;Lee, Sang-Whi;Jang, Seung-Wook
    • The Korean Journal of Financial Management
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    • v.21 no.2
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    • pp.99-123
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    • 2004
  • We focus in this study on incremental financing decisions and estimate a logit model for the probability a firm will choose a private placement over a public bond issue. We hypothesize that information asymmetry, financial risk, agent cost, and proprietary information may affect a firm's choice between public debt and private placements. We find that as the size of firm increases, the probability of choosing a private placement declines significantly. The age of the firm, however, is not a significant factor affecting the firm's choice between public and privately-placed bond. The coefficients on the firm's leverage and non-investment grade dummy are significantly positive, meaning firms with high financial risk and credit risk select private placements. The findings regarding agency-related variables, PER and Tobin's Q, are somewhat complex. We find significant evidence that firms with high PER prefer private placements to public bonds, suggesting that borrowers with options to engage in asset substitution or underinvestment are more likely to choose private placements. The coefficient of Tobin's Q is negative, but not significant, which weakly support the hold-up hypothesis. When we construct an interaction term on the Tobin's Q with a non-investment rating dummy, however, the Tobin's Q interaction term becomes positive and significant. Thus, high Tobin's Q firms with a speculative rating are significantly more likely to choose a private placement, regardless of the potential hold-up problems. The ratio of R&D to sales, proxy for proprietary information, is positively significant. This result can be interpreted as evidence in favor of a role for proprietary information in the debt sourcing decision process for these firms.

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Performance of Upflow Anaerobic Bioelectrochemical Reactor Compared to the Sludge Blanket Reactor for Acidic Distillery Wastewater Treatment (상향류식 혐기성 슬러지 블랭킷 반응조에 비교한 생물전기화학 반응조의 산성 주정폐수처리성능)

  • Feng, Qing;Song, Young-Chae;Yoo, Kyuseon;Lal, Banwari;Kuppanan, Nanthakumar;Subudhi, Sanjukta
    • Journal of Korean Society of Environmental Engineers
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    • v.38 no.6
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    • pp.279-290
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    • 2016
  • The performance of upflow anaerobic bioelectrochemical reactor (UABE), equipped with electrodes (anode and cathode) inside the upflow anaerobic reactor, was compared to that of upflow anaerobic sludge blanket (UASB) reactor for the treatment of acidic distillery wastewater. The UASB was stable in pH, alkalinity and VFAs until the organic loading rate (OLR) of 4.0 g COD/L.d, but it became unstable over 4.0 g COD/L.d. As a response to the abrupt doubling in OLR, the perturbation in the state variables for the UABE was smaller, compared to the UASB, and quickly recovered. The UABE stability was better than the UASB at higher OLR of 4.0-8.0 g COD/L.d, and the UABE showed better performance in specific methane production rate (2,076mL $CH_4/L.d$), methane content in biogas (66.8%), and COD removal efficiency (82.3%) at 8.0 g COD/L.d than the UASB. The maximum methane yield in UABE was about 407mL/g $COD_r$ at 4.0 g COD/L.d, which was considerably higher than about $282mL/g\;COD_r$ in UASB. The rate limiting step for the bioelectrochemical reaction in UABE was the oxidation of organic matter on the anode surface, and the electrode reactions were considerably affected by the pH at 8.0 g COD/L.d of high OLR. The maximum energy efficiency of UABE was 99.5%, at 4.0 g COD/L.d of OLR. The UABE can be an advanced high rate anaerobic process for the treatment of acidic distillery wastewater.

The Intelligent Determination Model of Audience Emotion for Implementing Personalized Exhibition (개인화 전시 서비스 구현을 위한 지능형 관객 감정 판단 모형)

  • Jung, Min-Kyu;Kim, Jae-Kyeong
    • Journal of Intelligence and Information Systems
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    • v.18 no.1
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    • pp.39-57
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    • 2012
  • Recently, due to the introduction of high-tech equipment in interactive exhibits, many people's attention has been concentrated on Interactive exhibits that can double the exhibition effect through the interaction with the audience. In addition, it is also possible to measure a variety of audience reaction in the interactive exhibition. Among various audience reactions, this research uses the change of the facial features that can be collected in an interactive exhibition space. This research develops an artificial neural network-based prediction model to predict the response of the audience by measuring the change of the facial features when the audience is given stimulation from the non-excited state. To present the emotion state of the audience, this research uses a Valence-Arousal model. So, this research suggests an overall framework composed of the following six steps. The first step is a step of collecting data for modeling. The data was collected from people participated in the 2012 Seoul DMC Culture Open, and the collected data was used for the experiments. The second step extracts 64 facial features from the collected data and compensates the facial feature values. The third step generates independent and dependent variables of an artificial neural network model. The fourth step extracts the independent variable that affects the dependent variable using the statistical technique. The fifth step builds an artificial neural network model and performs a learning process using train set and test set. Finally the last sixth step is to validate the prediction performance of artificial neural network model using the validation data set. The proposed model is compared with statistical predictive model to see whether it had better performance or not. As a result, although the data set in this experiment had much noise, the proposed model showed better results when the model was compared with multiple regression analysis model. If the prediction model of audience reaction was used in the real exhibition, it will be able to provide countermeasures and services appropriate to the audience's reaction viewing the exhibits. Specifically, if the arousal of audience about Exhibits is low, Action to increase arousal of the audience will be taken. For instance, we recommend the audience another preferred contents or using a light or sound to focus on these exhibits. In other words, when planning future exhibitions, planning the exhibition to satisfy various audience preferences would be possible. And it is expected to foster a personalized environment to concentrate on the exhibits. But, the proposed model in this research still shows the low prediction accuracy. The cause is in some parts as follows : First, the data covers diverse visitors of real exhibitions, so it was difficult to control the optimized experimental environment. So, the collected data has much noise, and it would results a lower accuracy. In further research, the data collection will be conducted in a more optimized experimental environment. The further research to increase the accuracy of the predictions of the model will be conducted. Second, using changes of facial expression only is thought to be not enough to extract audience emotions. If facial expression is combined with other responses, such as the sound, audience behavior, it would result a better result.

Dry Etching of GaAs and AlGaAs in Diffuion Pump-Based Capacitively Coupled BCl3 Plasmas (확산펌프 기반의 BCl3 축전결합 플라즈마를 이용한 GaAs와 AlGaAs의 건식 식각)

  • Lee, S.H.;Park, J.H.;Noh, H.S.;Choi, K.H.;Song, H.J.;Cho, G.S.;Lee, J.W.
    • Journal of the Korean Vacuum Society
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    • v.18 no.4
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    • pp.288-295
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    • 2009
  • We report the etch characteristics of GaAs and AlGaAs in the diffusion pump-based capacitively coupled $BCl_3$ plasma. Process variables were chamber pressure ($50{\sim}180$ mTorr), CCP power ($50{\sim}200\;W$) and $BCl_3$ gas flow rate ($2.5{\sim}10$ sccm). Surface profilometry was used for etch rate and surface roughness measurement after etching. Scanning electron microscopy was used to analyze the etched sidewall and surface morphology. Optical emission spectroscopy was used in order to characterize the emission peaks of the $BCl_3$ plasma during etching. We have achieved $0.25{\mu}m$/min of GaAs etch rate with only 5 sccm $BCl_3$ flow rate when the chamber pressure was in the range of 50{\sim}130 mTorr. The etch rates of AlGaAs were a little lower than those of GaAs at the conditions. However, the etch rates of GaAs and AlGaAs decreased significantly when the chamber pressure increased to 180 mTorr. GaAs and AlGaAs were not etched with 50 W CCP power. With $100{\sim}200\;W$ CCP power, etch rates of the materials increased over $0.3{\mu}m$/min. It was found that the etch rates of GaAs and AlGaAs were not always proportional to the increase of CCP power. We also found the interesting result that AlGaAs did not etched at 2.5 sccm $BCl_3$ flow rate at 75 mTorr and 100 W CCP power even though it was etched fast like GaAs with more $BCl_3$ gas flow rates. By contrast, GaAs was etched at ${{\sim}}0.3{\mu}m$/min at the 2.5 sccm $BCl_3$ flow rate condition. A broad molecular peak was noticed in the range of $500{\sim}700\;mm$ wavelength during the $BCl_3$ plasma etching. SEM photos showed that 10 sccm $BCl_3$ plama produced more undercutting on GaAs sidewall than 5 sccm $BCl_3$ plasma.