• Title/Summary/Keyword: Time-Frequency Analysis

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Influence of Chinese International Students' Family Strengths on Social Networking Services Addiction Tendency: Focusing on the Mediating Effect of Ego Resilience (중국 유학생의 가족건강성이 SNS 중독경향성에 미치는 영향: 자아탄력성의 매개효과를 중심으로)

  • JIANG, YUJING;Park, Jeoungyun
    • Journal of Family Resource Management and Policy Review
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    • v.27 no.4
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    • pp.19-33
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    • 2023
  • The purpose of this study was to examine the mediating effect of ego resilience on the relationship between family strengths of Chinese international students and Social Networking Services(SNS) addiction tendency. The data were collected through a survey of 349 Chinese international students studying in Korea and analyzed using the SPSS Statistics version 28 program and SPSS Process Macro 4.3. The main results are as follows. First, Chinese international students exhibited higher-than-average levels of SNS addiction tendency, family strengths, and ego resilience. Second, the SNS addiction tendency of Chinese international students had a significant positive correlation with the average time spend on SNS per day. while demonstrating a negative correlation with family strengths and ego resilience. Third, the hierarchical regression analysis revelated that gender, frequency of contact with family, average time spend on SNS per day, qualitative bond as a sub variable of family strengths, and control as a sub variables of ego resilience were significant factors influencing SNS addiction tendency of Chinese international students. Fourth, the study confirmed the complete mediation of ego resilience in the effect of family strengths on SNS addiction tendency. Based on the research results, this study suggested specific directions for counseling interventions aimed at mitigating SNS addiction tendencies among Chinese international students.

Analysis of Dietary Behavior and Related Factors According to the Level of Generalized Anxiety Disorder in Adolescents: Using the 16th-18th(2020-2022) Korea Youth Risk Behavior Survey (청소년의 범불안장애 수준에 따른 식생활 행태 및 관련 요인 분석: 제16차-제18차 (2020년-2022년) 청소년건강행태조사를 이용하여)

  • Kye, Eun Seul;Kim, Yookyung;Lee, Jung Woo
    • Journal of Korean Home Economics Education Association
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    • v.35 no.4
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    • pp.33-45
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    • 2023
  • The purpose of this study is to investigate the association between dietary behavior and related factors according to the generalized anxiety disorder (GAD) in adolescents. The results of analyzing demographic characteristics according to the GAD showed that gender, age, BMI, type of school, residence type, father's nationality, smoking and drinking experience, perceived health status, perception of body shape, economic status, academic achievement, physical activity, sedentary time and smartphone usage time were related to the GAD (p<0.01). The results of analyzing dietary behavior according to the GAD showed that the frequency of water intake, sweetened beverage intake, fast food intake, fruit intake and breakfast intake were related to the GAD (p<0.001). The results of analyzing depression and suicidality according to the GAD showed that depression, suicidal ideation, planning, and attempts were all related to the GAD (p<0.001). Even after adjusting for factors corresponding to demographic characteristics, it was confirmed that the level of GAD had a significant effect on depression and suicidality. This study is significant in that it provided basic data on adolescent mental health problems by analyzing dietary behavior and related factors according to the level of GAD.

A STATISTICAL ANALYSIS OF SOLAR WIND DYNAMIC PRESSURE PULSES DURING GEOMAGNETIC STORMS (지자기폭풍 기간 동안의 태양풍 동압력 펄스에 관한 통계적 분석)

  • Baek, J.H.;Lee, D.Y.;Kim, K.C.;Choi, C.R.;Moon, Y.J.;Cho, K.S.;Park, Y.D.
    • Journal of Astronomy and Space Sciences
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    • v.22 no.4
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    • pp.419-430
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    • 2005
  • We have carried out a statistical analysis on solar wind dynamic pressure pulses during geomagnetic storms. The Dst index was used to identify 111 geomagnetic storms that occurred in the time interval from 1997 through 2001. We have selected only the events having the minimum Dst value less than -50 nT. In order to identify the pressure impact precisely, we have used the horizontal component data of the magnetic field H (northward) at low latitudes as well as the solar wind pressure data themselves. Our analysis leads to the following results: (1) The enhancement of H due to a pressure pulse tends to be proportional to the magnitude of minimum Dst value; (2) The occurrence frequency of pressure pulses also increases with storm intensity. (3) For about $30\%$ of our storms, the occurrence frequency of pressure pulses is greater than $0.4\#/hr$, implying that to. those storms the pressure pulses occur more frequently than do periodic substorms with an average substorm duration of 2.5 hrs. In order to understand the origin of these pressure pulses, we have first examined responsible storm drivers. It turns out that $65\%$ of the studied storms we driven by coronal mass ejections (CMEs) while others are associated with corotating interaction regions $(6.3\%)$ or Type II bursts $(7.2\%)$. Out of the storms that are driven by CMEs, over $70\%$ show that the main phase interval overlaps with the sheath, namely, the region between CME body and the shock, and with the leading region of a CME. This suggests that the origin of the frequent pressure pulses is often due to density fluctuations in the sheath region and the leading edge of the CME body.

Incidence and Spectrum of Chromosomal Abnormalities associated with Spontaneous Abortions in Korea: 470 Products of Conception over a Period of 6 Years (2005-2010) (국내 자연유산에 의한 수태산물 핵형분석에서 관찰된 염색체 이상의 발생율과 유형: 6년(2005-2010)간 수태산물 470예 분석)

  • Han, Sung-Hee;An, Jeong-Wook;Yang, Young-Ho;Kim, Young-Jin;Cho, Han-Ik;Lee, Kyoung-Ryul
    • Journal of Genetic Medicine
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    • v.8 no.1
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    • pp.44-52
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    • 2011
  • Purpose: Cytogenetic analysis of spontaneous abortions (SABs) provides valuable information to establish the causes of fetal loss, information that is essential to provide accurate reproductive and genetic counseling couples. Such analysis also provides information on the frequencies and types of chromosomal abnormalities and associated risks of recurrence. However, there have only been a few reports of chromosomal abnormalities in small samples of SABs in the Korean population. Here, we report the incidence and spectrum of chromosomal abnormalities for cases of 470 SAB in Korea. Material and Methods: Between 2005 and 2010, a total of 470 products of conception (POC) resulting from SABs were submitted to our laboratory for cytogenetic analysis from various medical sites in Korea. The incidences and types of specific chromosomal abnormalities were determined. The abnormalities were distinguished by gestational age at the time of SAB and by maternal age. Results: The frequency of chromosomal abnormalities in POCs was 54.3% (255/470), including 228 (89.3%) numerical and 27 (10.7%: 3 balanced and 24 unbalanced) structural abnormalities. Among the numerical abnormalities, trisomy was predominant (67.0%), followed by monosomy X (12.5%), polyploidy (8.2%), triple X (0.8%), and autosomal monosomy (0.8%). The overall sex ratio (male: female) among the 470 POCs with normal and abnormal karyotypes were 0.58 and 0.65, respectively. Trisomies were identified for each autosome, with the exceptions of 1, 3, and 19. Among the 171 autosomal trisomies, trisomy 16 was the most common (19.9%), followed by trisomy 22 (13.5%), trisomy 21 (12.3 %), trisomy 15 (9.9%), and trisomies 18 and 13 (5.3%). The frequency of chromosomal abnormalities decreased with gestational age and increased with maternal age, but only because of increases in trisomies and complex abnormalities. Conclusions: We have presented a large collection of cytogenetic data for SABs collected during the past 6 years and provided a database for prenatal genetic counseling of parents who have experienced SABs in Korea.

A Comparative Study on the Perception of A Beautiful Landscape According to the Differences of Living Environment (성장환경의 차이에 따른 아름다운 경관 인지의 비교연구 -도시와 농촌 국민학생을 대상으로-)

  • 성현찬;임승빈
    • Journal of the Korean Institute of Landscape Architecture
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    • v.20 no.3
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    • pp.64-78
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    • 1992
  • In this study, elementary school students of both urban and rural areas as its subjects were asked to draw 'A beautiful landscape' by employing the perspective representation technique, i. e., the Perception Map, and to write down the elements comprising 'A beautiful landscape' in the questionnaire sheets. By doing so, an attempt was made 1) to analyze whether there are differences in perceiving 'A beautiful landscape' according to the differences of the environment in which they were brought up ; and, if there are differences. 2) to identify them ; and based on that , 3) to present basic data for evaluation on landscape, on its preference analysis and for Park Planning. The summary of this study is as follows ; 1) The main elements, elementary school students think, comprising 'A beautiful landscape' are 25 ones such as Sky(7), Sea(2), Water(2), Topography(5), Plants(5), Animals(3), School(1), Rural village(1). The natural elements showing a difference are ; Water fall in urban areas and School landscape in rural areas ; the artificial elements are ; City groups(Structures, Facilities, Necessities, Transportation means and Space) in urban areas and School groups in rural areas. Especially, in case of rural area children, they regard 'Trees' as an essential element to be 'A beautiful landscape' comparing to those in urban areas. 2) According to the analysis result on the correlation between the elements comprising a beautiful rural landscape and a beautiful ruban landscape, the correlation between boys and girls is high, showing the same trend with any difference. In comparison of urban areas with rural areas, there is no difference between natural elements, but in artificial elements(7 groups without family) the correlation is quite low, showing that all comprising elements are not the same between rural schools and cities, between schools within the same areas, and between schools of different areas. 3) In identifying the names of elements comprising 'A beautiful landscape', Back-Du Mountain and Sorak Mountain are shown the highest frequency in the category of mountains. In the names of trees and flowers, the elementary school children are thought to consider the kinds of trees and flowers they can see always at hand, i. e., those in their school ground where they spend most of their day time. 4) In the analysis of the numbers of comprising elements according to the responses in the questionnaire sheets and in the Perception Map, 'less than 10' is the most frequently counted number of comprising elements by individual students regardless of rural and urban differences. When the total frequency is divided by the number of students, the mean score is 6-7 without any differences between rural and urban areas, implying that there are no differences in the expression ability between urban and rural schools. 5) According to the result of classyfying and analysizing the landscape appeared on the Perception Map by similar elements and by similar scenes, 'A beautiful landscape' thought by elementary school children is defined not as a standardized form but as 11 types such as the landscape of fields, the landscape of a sea, the landscape of a rural village, a type where elements are assembled, the landscape of cities, the landscape of a school, the landscape coming out of a imagination, and other landscape. Both rural and urban children all consider the landscape of mountains and field and the landscape where several elements are assembled as a commonly beautiful one. Among the landscapes showing rural and urban differences, it can be analyzed that urban children regard the landscapes of cities, imagination, and waterfalls as something characteristic, while rural children regard the landscape of schools and rural villages as something characteristic.

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Analysis of comparisons of eating-out, dietary lifestyles, and healthy dietary competencies among middle-aged consumers according to obesity status and gender for implications of consumer education (소비자교육을 위한 중년기 소비자의 성별, 비만도별 외식 행동, 식생활 라이프스타일 및 건강한 식생활역량의 차이 분석)

  • Park, Jong Ok
    • Journal of Nutrition and Health
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    • v.51 no.1
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    • pp.60-72
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    • 2018
  • Purpose: The purpose of this study was to determine differences in eating-out, dietary life styles, and healthy dietary competencies among middle-aged consumers according to obesity status and gender for implications of consumer education. Methods: Data were drawn from the 2016 Food Consumption Behavior Survey, and 3,022 subjects (mail 1,388; female 1,634) who were middle-aged adults were investigated. Analysis of variance with $Scheff\acute{e}$ test, t-test, $x^2$-test, and factor analysis were performed using SPSS v.24. Results: Males showed less interest in diet than females. For both males and females, higher BMI degrees were associated with higher levels of interest in diet. For frequency, monthly average consumption expenditure, one-time cost for eating out, and drinking frequency, males showed higher levels than females. Especially for the male group, higher obesity status was associated with higher levels of eating out and drinking. Dietary lifestyles of males and females turned out to be very similar. For the male group, normal weight group was more likely to show 'health and high quality pursuit dietary life-style' than the other groups. For females, the normal weight group were more likely to show 'health and high quality pursuit dietary life-style' and 'safety pursuit dietary life-style' than the other groups. The level of 'healthy dietary competence' for females was found to be higher than that for males. For the female group, there were significant differences according to obesity status, and practice was more important than knowledge in determining a healthy dietary life. Conclusion: For dietary life-related education for obese middle-aged consumers, it is important to emphasize less eating-out and drinking and less overeating while eating-out based on the results that eating-out, drinking, and overeating in the obesity group were significantly higher than in the normal group. It is important to focus on the value of dietary life and diverse foods, based on the results that the obesity group was less likely to be have healthy dietary lifestyles and consume less diverse foods than the normal group.

A STUDY ON THE TEMPERATURE CHANGES OF BONE TISSUES DURING IMPLANT SITE PREPARATION (임플랜트 식립부위 형성시 골조직의 온도변화에 관한 연구)

  • Kim Pyung-Il;Kim Yung-Soo;Jang Kyung-Soo;Kim Chang-Whe
    • The Journal of Korean Academy of Prosthodontics
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    • v.40 no.1
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    • pp.1-17
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    • 2002
  • The purpose of this study is to examine the possibility of thermal injury to bone tissues during an implant site preparation under the same condition as a typical clinical practice of $Br{\aa}nemark$ implant system. All the burs for $Br{\aa}nemark$ implant system were studied except the round bur The experiments involved 880 drilling cases : 50 cases for each of the 5 steps of NP, 5 steps of RP, and 7 steps of WP, all including srew tap, and 30 cases of 2mm twist drill. For precision drilling, a precision handpiece restraining system was developed (Eungyong Machinery Co., Korea). The system kept the drill parallel to the drilling path and allowed horizontal adjustment of the drill with as little as $1{\mu}m$ increment. The thermocouple insertion hole. that is 0.9mm in diameter and 8mm in depth, was prepared 0.2mm away from the tapping bur the last drilling step. The temperatures due to countersink, pilot drill, and other drills were measured at the surface of the bone, at the depths of 4mm and 8mm respectively. Countersink drilling temperature was measured by attaching the tip of a thermocouple at the rim of the countersink. To assure temperature measurement at the desired depths, 'bent-thermocouples' with their tips of 4 and 8mm bent at $120^{\circ}$ were used. The profiles of temperature variation were recorded continuously at one second interval using a thermometer with memory function (Fluke Co. U.S.A.) and 0.7mm thermocouples (Omega Co., U.S.A.). To simulate typical clinical conditions, 35mm square samples of bovine scapular bone were utilized. The samples were approximately 20mm thick with the cortical thickness on the drilling side ranging from 1 to 2mm. A sample was placed in a container of saline solution so that its lower half is submerged into the solution and the upper half exposed to the room air, which averaged $24.9^{\circ}C$. The temperature of the saline solution was maintained at $36.5^{\circ}C$ using an electric heater (J. O Tech Co., Korea). This experimental condition was similar to that of a patient s opened mouth. The study revealed that a 2mm twist drill required greatest attention. As a guide drill, a twist drill is required to bore through a 'virgin bone,' rather than merely enlarging an already drilled hole as is the case with other drills. This typically generates greater amount of heat. Furthermore, one tends to apply a greater pressure to overcome drilling difficulty, thus producing even greater amount heat. 150 experiments were conducted for 2mm twist drill. For 140 cases, drill pressure of 750g was sufficient, and 10 cases required additional 500 or 100g of drilling pressure. In case of the former. 3 of the 140 cases produced the temperature greater than $47^{\circ}C$, the threshold temperature of degeneration of bone tissue (1983. Eriksson et al.) which is also the reference temperature in this study. In each of the 10 cases requiring extra pressure, the temperature exceeded the reference temperature. More significantly, a surge of heat was observed in each of these cases This observations led to addtional 20 drilling experiments on dense bones. For 10 of these cases, the pressure of 1,250g was applied. For the other 10, 1.750g were applied. In each of these cases, it was also observed that the temperature rose abruptly far above the thresh old temperature of $47^{\circ}C$, sometimes even to 70 or $80^{\circ}C$. It was also observed that the increased drilling pressure influenced the shortening of drilling time more than the rise of drilling temperature. This suggests the desirability of clinically reconsidering application of extra pressures to prevent possible injury to bone tissues. An analysis of these two extra pressure groups of 1,250g and 1,750g revealed that the t-statistics for reduced amount of drilling time due to extra pressure and increased peak temperature due to the same were 10.80 and 2.08 respectively suggesting that drilling time was more influenced than temperature. All the subsequent drillings after the drilling with a 2mm twist drill did not produce excessive heat, i.e. the heat generation is at the same or below the body temperature level. Some of screw tap, pilot, and countersink showed negative correlation coefficients between the generated heat and the drilling time. indicating the more the drilling time, the lower the temperature. The study also revealed that the drilling time was increased as a function of frequency of the use of the drill. Under the drilling pressure of 750g, it was revealed that the drilling time for an old twist drill that has already drilled 40 times was 4.5 times longer than a new drill The measurement was taken for the first 10 drillings of a new drill and 10 drillings of an old drill that has already been used for 40 drillings. 'Test Statistics' of small samples t-test was 3.49, confirming that the used twist drills require longer drilling time than new ones. On the other hand, it was revealed that there was no significant difference in drilling temperature between the new drill and the old twist drill. Finally, the following conclusions were reached from this study : 1 Used drilling bur causes almost no change in drilling temperature but increase in drilling time through 50 drillings under the manufacturer-recommended cooling conditions and the drilling pressure of 750g. 2. The heat that is generated through drilling mattered only in the case of 2mm twist drills, the first drill to be used in bone drilling process for all the other drills there is no significant problem. 3. If the drilling pressure is increased when a 2mm twist drill reaches a dense bone, the temperature rises abruptly even under the manufacturer-recommended cooling conditions. 4. Drilling heat was the highest at the final moment of the drilling process.

The Trend of Nursing Research in Korea on Mother-Child Relationship (모아관계에 관한 국내 간호연구 동향)

  • Paik Seung Nam;Kim Jeong Hwa;Wang Myung Ja;Sung Mi Hae;Cho Kyoul Ja
    • Child Health Nursing Research
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    • v.2 no.1
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    • pp.55-68
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    • 1996
  • Although nursing researchers have performed studies on parent-child relationship actively since early 1980s in Korea, nothing hasn't been tried on the analysis of the contents of researches. We researchers tried examining the trend of researches by investigating treaties on mother-child relationship conducted from 1981 to 1994. The purpose of this study was to analyze the trend of research on the mother-child relationship and to suggest direction for future study. The total numbers of the studies were 27 cases, These studies were analyzed for 1) time of publication 2) research design 3)main concept 4)thesis for a degree or nondegree 5) measurement tool The finding of the analysis were as follows. 1) In the chronological situation, the research on mother-child relationship began to perform in 1981 in the country and had been made most for five years to 1986 with 14 treaties and has decreased since 1990. 2) In the research plan, there are 21 survey(the most) ,5 quasi experimental(before 1986), 1 qualitative. 3) In the subject, the researches on mother-child are the most, 22 and of them 17 treaties on normal infant,4 comparative research on high risk infant and normal infant,5 treaties on mother, 4) The conception of mother-child relationship was used as various conceptions such as affection, union, bonding in early research of 1980s, but it hasn't been used as union bonding but studied mostly as the conception of 'mother-child interaction'since 1986. 5) The measurement tool of research was used variously, the Cropley's tool was used in early 1980s, but Walker's MIPS, Barnard's NCAST were used mostly in 1990. 6) Mother-child interaction influence on mother's self-conception, stress, care and feeding of child, frequency of delivery, planned pregnancy and delivery and health condition of child, birth weight, fetal period, period of mother-child life. Aspects of mother-child interaction composed on visual contact, looking at each other, skinship and caress with finger and fingertip. The leading action of mother-child interaction was mostly uttering action. 7) I suggest that the program for professional education is necessary for the establishment of the aspects of mother-child interaction.

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Fragility Analysis Method Based on Seismic Performance of Bridge Structure considering Earthquake Frequencies (지진 진동수에 따른 교량의 내진성능기반 취약도 해석 방법)

  • Lee, Dae-Hyoung;Chung, Young-Soo;Yang, Dong-Wook
    • Journal of the Korea Concrete Institute
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    • v.21 no.2
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    • pp.187-197
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    • 2009
  • This paper presents a systematic approach for estimating fragility curves and damage probability matrices for different frequencies. Fragility curves and damage probability indicate the probabilities that a structure will sustain different degrees of damage at different ground motion levels. The seismic damages are to achieved by probabilistic evaluation because of uncertainty of earthquakes. In contrast to previous approaches, this paper presents a method that is based on nonlinear dynamic analysis of the structure using empirical data. This paper presents the probability of damage as a function of peak ground acceleration and estimates the probability of five damage levels for prestressed concrete (PSC) bridge pier subjected to given ground acceleration. At each level, 100 artificial earthquake motions were generated in terms of soil conditions, and nonlinear time domain analyses was performed for the damage states of PSC bridge pier structures. These damage states are described by displacement ductility resulting from seismic performance based on existing research results. Using the damage states and ground motion parameters, five fragility curves for PSC bridge pier with five types of dominant frequencies were constructed assuming a log-normal distribution. The effect of dominant frequences was found to be significant on fragility curves.

Profiling Approach for the Choice between Speculation and Postponement Strategy in Supply Chain Management (공급사슬관리의 예측전략과 지연전략 선택을 위한 프로파일링 접근법)

  • Kang, Sung-Wook;Kim, Gyu-Bae
    • Journal of Distribution Science
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    • v.12 no.4
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    • pp.47-54
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    • 2014
  • Purpose - The postponement strategy, which delays the form, place, and production of products as late as possible, has been widely considered as a competitive supply chain management scheme in an era of mass customization and modular manufacturing. An interesting business phenomenon is that not all manufacturing/logistics firms choose the postponement strategy. Given that postponement is a counter-measure to speculation, which has some advantages under certain environments, the current imprudent inclination toward the postponement strategy may cause firms to lose the potential of the speculation strategy, an alternative strategy in supply chain management. Building on the logistics and manufacturing literature, this study examines characteristics of two contrasting strategies, postponement and speculation, and major factors favoring each strategy. Research design, data, and methodology - We apply the profiling approach to two business cases, HP printer and LG mobile phone. The profiling approach is a method of choosing a particular strategy aligned with environmental factors. While various approaches have been used to check the fit between a business strategy and environmental factors, the literature on manufacturing strategy and logistics has commonly adopted the profiling approach. Major factors used in profiling variables are derived from the literature. Two samples, HP printer and LG mobile phone, are selected, because they represent major characteristics appropriate for each strategy. The profiling is based on data from semi-organized interviews with managers. Results - The profiling approach shows that the postponement strategy is a suitable one for HP printers. Most factors, such as product life cycle, large production volume, low-price, product value, and monetary density, support delaying end products until as late as possible. Despite some exceptions, such as delivery time and economy of scale, our analysis states that the overall profile of HP printer is favorable for the postponement strategy. On the other hand, LG mobile phone may adapt the speculation strategy. Although it has large production volume and low delivery frequency, most characteristics support the speculation strategy for this product. An interesting finding is that, despite common perception that advanced technology products such as mobile telephones favor the postponement strategy, profiling proposes the speculation strategy for this product. Conclusions - Our analysis shows that speculation is not the universal option for supply chain management, and that, when choosing a specific strategy, one should consider many factors simultaneously. A major implication of our work is to emphasize the role of environmental factors such as supply chain variables in choosing an inventory strategy, and the importance of fit rather than solely strategic orientation. A theoretical contribution is to demonstrate the benefit of the simultaneous consideration of business variables in choosing specific strategies. For practitioners, our work leads us to consider the existence and the potential of speculation as a counter-measure to postponement. In addition, the comprehensive framework in this research may be instantly used in examining a practical strategy.